CAÍDA
DE BLOQUES/METEOROS DE HIELO EN ESPAÑA
"Ciencia es creer en la ignorancia de los científicos. Richard Phillips Feynman, Premio Nobel de Física, 1965"
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CAÍDA
DE BLOQUES/METEOROS DE HIELO EN ESPAÑA
"Ciencia es creer en la ignorancia de los científicos. Richard Phillips Feynman, Premio Nobel de Física, 1965" |
 Página
informativa sobre los mal llamados "aerolitos" diseñada y mantenida
por
Jesús
Martínez-Frías. Este website está hospedado en
TIERRA: Red Temática de Ciencias de la Tierra de España
 |
 martinezfrias@mncn.csic.es |
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Austria (2000),
Italia (2000), Holanda (2000), Argentina (2000), Colombia (2000), Australia (2001) USA (2002) |
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según distintos autores |
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por su eje de simetría en lugar de centro. Indica que su formación tuvo lugar dentro de vórtices por acreción de gotitas de agua sobreenfriada en cumulonimbos |
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diferencia de los grandes “hailstones”. Sigue a Griffiths. |
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de gotas y vapor fueran transportadas hasta grandes altitudes por tornados, antes de ser enfriadas y convertidas en bloques de hielo. Mecanismo que evite la dispersión ? |
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dos tipologías atmosféricas: GWP1 para éstos y GWP5 para los “hailstones”. Define las hipótesis de Griffiths y Crew. |
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A History of Ice Falls
Mysterious ice falls have been reported
in many parts of the world for centuries – many
before the invention of flying
machines. Here are some of the most extraordinary examples
of documented ice falls:
In the late 1700s, a gargantuan
chuck of ice “as big as an elephant” was said to fall on
Seringapatam, India, and took three
days to melt.
In 1802, a lump of ice fell from the sky on Hungary that had a volume of 18 cubic feet!
In 1849, a block of ice that was
estimated to weigh a half a ton fell on the Balvullich farm
in Ord, Scotland. It measured about
20 feet in diameter and was reported to be crystal
clear, although apparently made
up of many cubes and diamond-shaped hunks of ice
fused together.
Another ice fall took place in Scotland
in December of 1950. A man driving near the town
of Dumbarton was nearly struck
by a rain of ice that crashed down onto the road. A
subsequent police investigation
weighed the collected ice at 112 pounds. Several other
reports of ice falls were recorded
in Great Britain in 1950 and 1951.
A carpenter working on a roof in
Kempton, West Germany in 1951 was struck and killed
by a 6-foot long, 6-inch around
rod of solid ice.
Farmer Edwin Groff of Bernville,
Pennsylvania was witness to a 50-pound, white globe of
ice that whooshed through the sky
and crashed on his property in 1957. A few seconds
later, a second ball of ice, half
the size of the first, smashed into his flower bed, just a few
yards from where he was standing.
On September 2, 1958, Dominick Bacigalupo
was knocked from his feet when a
70-pound ball of ice tore through
his roof and attic and broke into three pieces on his
kitchen floor.
The roof of the Phillips Petroleum
Plant in Woods Cross, Utah was punctured by a
50-pound block of ice in 1965.
One well-documented ice fall was
actually witnessed by a British meteorologist in 1973.
While standing on a street corner
in Manchester, R.F. Griffiths saw a huge chunk of ice
smash to pieces on the road just
10 feet away. The largest piece, which he recovered,
weighed 3-1/2 pounds.
A football-sized chunk of ice landed
in a garden near Lake Vattern, Sweden in 1990. It
was described as being somewhat
milky in appearance, dotted with bits of debris colored
gray, brown, and lilac.
A year later, in October 1991, a
20-pound mass of ice smashed through the roof of the
home of Mrs. Mavis Anderson in
West Yorkshire, England, landing in her kitchen.
In 1992, a sphere of yellow-tinged
ice crashed through the roof of a factory in Salihli,
Turkey. Witnesses said the ice
released the odor of rotting fruit as it melted. This sounds
like a candidate for airplane waste,
but officials determined there were no planes flying in
the area at the time.
1500-Pound ice chunk falls from sky
June 26, 1985. Hartford, Connecticut.
"Scientists yesterday tried to determine
the origin of a 1500-pound sheet of ice that
mysteriously dropped from the sky
and smashed into a backyard fence. David H. Menke,
directory of the Copernican Observatory
and Planetarium, said the ice was probably 6
feet long, 8 inches thick and moving
at about 200 mph. 'It's unusual in the fact that it fell
from the sky,' said Craig Robinson,
curator at the planetarium. 'That does not happen
often.' A 13year-old boy was in
his backyard Monday with a friend when the ice came
'whirling' from the sky and smashed
into the fence about 10 feet away from them."
China ``ice meteorite''
By Jeffrey Parker
April 2, 1995
BEIJING, April 2 (Reuter) - Chinese experts, saying it
could be a scientific first, have
recovered what they believe to be chunks of meteoric
ice that plummeted to earth in
Zhejiang province, Xinhua news agency said.
It was a happy coincidence that amateur geologist Zhong
Gongpei was nearby on March
23 when farmers saw three large chunks of ice crash with
a whoosh into the paddy fields
of Yaodou village, the official agency said late on Saturday.
Meteorite expert Wang Sichao of China's prestigious Purple
Mountain Observatory in
Jiangsu province said two chunks recovered by Zhong were
probably ice meteorites but
that further analysis was needed for confirmation, Xinhua
reported.
No ice meteorite has ever been verified by scientists
before, Wang said. If confirmed, the
meteoric find would be China's second major scientific
triumph this year.
Paleontologists at prestigious Beijing University said
in March they had extracted DNA
from a fossilised dinosaur egg, calling the find a major
step forward for mankind and one
that could add fact to the fictional hit movie "Jurassic
Park" in which the extinct giants were
cloned back to life.
Scientists culled the DNA from a "cotton-like" part on
the inner surface of an egg found in
central China. Extensive analysis left them convinced
the DNA could only be that of a
dinosaur, they said.
Experts are viewing what portends to be the world's first
recovery of an ice meteorite with
excitement and caution.
"According to witnesses, it fell with a 'whooo-ing' sound,
with a cloudy streak, then came
crashing down into three fields about one km (0.6 miles)
apart," Xinhua said.
Zhong rushed to the scene, recovered two pieces and sent
both to Purple Mountain on
March 29 with the aid of a frozen food company, which
kept them from melting.
The largest chunk, now about the size of a fist, left
a crater about one metre (3.3 ft) in
diameter and a half metre deep. The second piece was
a bit smaller, Xinhua said.
Wang, a member of the International Meteorite Council,
cited strong evidence that the ice
chunks were from a meteor that crashed from space into
the earth's atmosphere.
"Three pieces of ice falling together trailing a cloudy
streak have never been seen before,"
Xinhua quoted Wang as saying.
"They are white, semi-transparent, with an irregular shape
and what are apparently air
bubbles on both the surface and inside the ice. Unlike
man-made ice, the ice has air
bubbles, is relatively light and doesn't have the layered
structure of hailstones," he said.
"Judging from this, they can only be seen to be ice meteorites," he said.
Further tests will involve closer inspection of the molecular
and atomic structure of the ice.
Experts want to analyse the ice for isotopes and cosmic
dust, Wang said.
Consultations with the International Meteorite Council may also be necessary, he added.
1500-POUND ICE CHUNK FALLS FROM SKY
June 26, 1985. Hartford, Connecticut.
"Scientists yesterday tried to determine
the origin of a 1500-pound
sheet of ice that mysteriously
dropped from the sky and smashed
into a backyard fence. David H.
Menke, directory of the
Copernican Observatory and Planetarium,
said the ice was
probably 6 feet long, 8 inches
thick and moving at about 200 mph.
'It's unusual in the fact that
it fell from the sky,' said Craig
Robinson, curator at the planetarium.
'That does not happen
often.' A 13year-old boy was in
his backyard Monday with a friend
when the ice came 'whirling' from
the sky and smashed into the
fence about 10 feet away
from them."
The remainder of the article gives
the opinions of some scientists who were
contacted about the fall.
The director of the observatory thought the ice
probably fell off the wing of an
aircraft. The director of the American Meteor
Society suggested a cosmic origin,
providing the ice were pure. An astronomy
professor assured everyone that
it couldn't be cometary, because the sun
would melt particles of ice in
outer space. Instead, he opted for strong
thunderstorm winds picking
the ice up from "somewhere" and dropping it on
Hartford! (Anonymous; "1,500-Pound
Ice Chunk Falls from Sky," Manchester
(NH) Union Leader, June 27, 1985.
Cr. B. Greenwood via L. Farish)
Reference. Anomalous ice falls are
cataloged in GWF1 in our catalog:
Tornados, Dark Days. For ordering
information, visit: here.
From Science Frontiers #43, JAN-FEB
1986. © 1986-2000 William R. Corliss
A short summary regarding the Swedish incidents:
On October 25th 1999 at 11.10 GMT Mr Bengt Persson in
Eskilstuna west of
Stockholm heard a loud bang and looked out of his window.
Outside at the
parking lot he saw that his cars front window was broken
and that several
<>
I have also written about an earlier report from outside
the town of
Nyköping, South of Stockholm, from September 5th
1981. A man walking in the
woods heard a strange noise from the sky and looked up.
After a short time
he saw an object coming down through the air crashing
to the ground. When
he approached the place of impact he saw that the debris
was made of ice.
Seconds later another object fell not far from him.
There are several other instances of ice falls in Sweden.
As far as I know
all of them can be attributed to air craft. One man in
Upplands-Väsby north
of Stockholm wrote and told me about an incident where
his roof tiles were
damaged by falling ice. The Swedish aviation authority
examined the ice and
concluded it to come from an air craft.
This is all I have for now. Please write again if you
have more questions.
If you publish anything about the ice falls I would very
much appreciate a
copy.
Yours
Clas Svahn
Dagens Nyheter
S-105 15 Stockholm
Sweden
Monday January 31, 2000
Ball of ice slams into Barrhaven house
'It sounded like a hand grenade'
Carrie Buchanan
The Ottawa Citizen
Chris Mikula, The Ottawa Citizen / Bob Laing of Barrhaven
holds up the five-kilogram
chunk of ice that crashed into his house early Saturday
afternoon. Mr. Laing plans to call
the Department of Transport to see if it fell from a
plane.
Bob Laing of Barrhaven was sitting in his family room
early Saturday afternoon when
something hit his roof with a loud bang.
"It sounded like a hand grenade going off, and you could
hear a rumble as it rolled off the
roof," he said.
He didn't find the object until yesterday, when he discovered
a ball of ice shaped like a
basketball outside the dining room window of his home
on Pepperrall Crescent. It
weighed about five kilograms.
"I could see there were little stones from shingles that
were embedded, and there was,
like, tar from shingles, so I knew that it was the thing
that hit the roof," he said.
But there wasn't very much of the roof material stuck to the ball. "It was pure ice," he said.
"If it had ever hit anybody it'd have killed them," said
Mr. Laing, 74, who planned to call
the federal Department of Transport today to find out
whether they're interested in
examining it further.
It might have come from an airplane, he suggested, or
it might be space debris, perhaps
from a comet.
"There was a case in Spain where these things were falling
and they were all wondering
about it," said Mr. Laing, who saw news reports about
the Spanish incidents. Indeed,
between Jan. 8 and 20 about 30 such ice balls, also described
as the size and shape of
basketballs, fell throughout Spain, puzzling scientists
there.
Though a number of the Spanish ice hunks were thought
to have been practical jokes
perpetrated after initial reports of the phenomenon,
scientists in Spain were taking the
matter seriously. At first, they thought it might have
been sewage dropped by airplanes,
but the icy chunks were found to be almost pure water.
At least one sample, analysed in a laboratory, also contained
sodium chloride, or table
salt, and chalk, which weakens the theory they may have
come from a comet.
Mr. Laing was concerned enough to carefully preserve the
Barrhaven ice ball: He
wrapped it in two plastic bags, one over the other in
case of leaks, and placed it in his
freezer.
"The government, they can cut it open. I'm going to keep
it in the freezer and they can
have a look at it," he said last night.
"It's certainly not sewage, you can see that, it's pure
water," he said. But it could still have
fallen from an airplane, he said. "There's lots of airplanes
flying around here."
Meteorologist Tim Bullock of Environment Canada said he
could think of no weather
phenomenon to explain the falling ice.
But there was some cloud, quite high up in the sky on
Saturday, that could have formed
ice on an airplane, he speculated. This ice might have
dropped when the airplane lowered
its gear to prepare for a landing at the nearby Ottawa
Airport.
"That is sheer speculation, not even having seen it (the ice ball)" Mr. Bullock stressed.
Also, Mr. Bullock said he could not comment on the likelihood
of any kind of space
debris such as a comet or meteorite. "Rocks and meteorites
are out of our jurisdiction," he
said.
Mr. Laing said there are no tree branches over his house,
or any other structure the ice
could have fallen from, but many airplanes do fly over
his house on the way to the airport.
He's still not sure how much damage the impact did to
his roof.
"I'm an old man, so I couldn't go up and see," he said.
"I'll know the first rainstorm I
guess."
"This thing hitting my roof, it's a chance in a billion,"
he laughed, "yet I buy sweepstakes
(tickets) all the time and I never win."
Otro caso reciente de Canadá
Ice chunk crash
by Robert Drinkwater, Medicine Hat News, 15 February 2000
Glen Newman says he doesn't think kids are to blame for a chunk of ice that crashed through the plastic cap of his pickup truck as he was driving through Ross Glen over the weekend. He thinks the ice fell off a passing airplane."It made a loud bang and the truck vibrated around," Newman says. "I looked around but didn't see any kids or other vehicles around at the time."Newman says he was on his way to the store on Saturday to exchange a sweater he got for Christmas that was too big. It was about 3:30 p.m. and he was travelling near Ross Glen school when he heard the bang.He stopped his truck, got out, and saw a hole in the top corner of the bed cover. He said the ice must have come from above and must have been travelling at great speed to have punched through the cover without shattering.Newman thinks it came from a plane and says he plans to take the ice to a medical laboratory for testing to see if it might be frozen sewage from a plane."It's still in the truck and it's still frozen," Newman says, noting that he does not want to keep the ice in his freezer in case it actually is frozen sewage.
Transport Canada spokesperson Neil Green in Edmonton said the department's civil aviation inspectors were at a convention in Winnipeg and could not be reached for comment Monday about whether clear ice could fall from planes.Students at Ross Glen school made ice sculptures out of frozen blocks several weeks ago and chunks of the sculptures remain on the school's lawn. Most of the blocks were coloured but a few were clear.Vice-principal Dale Klaudt says after a few days, the sculptures became targets for children. He says he cannot say whether the ice that hit Newman's truck came from one of the sculptures."There's all kinds of kids that go by the front of the school," he says. Medicine Hat Police Staff Sgt. Don Girling says he is not aware of any other reports of ice hitting vehicles over the weekend and says there were no reports of mischief against vehicles, either.He says if the ice had enough velocity to smash through the truck cap, it would need to have been thrown straight up in the air. That, he says, would mean whoever threw it would have to be nearby.
Environment Canada meteorologist Ole Jacobsen in Calgary,
meanwhile, says the chunk that crashed through Newman's truck was larger
than even the heaviest hail and would not be able to stay airbourne long
enough to form naturally."My belief is that this is very unlikely to have
been a meteorological event," Jacobsen says.Girling says he has seen situations
where large pieces of ice have fallen off trucks while they were on overpasses
and have crashed down on cars underneath but that is unlikely to explain
what happened in Ross Glen.He says it is not the first time someone has
reported ice falling from the sky in Medicine Hat although he says he has
not heard of one in recent years. He says he is not sure what to make of
this one."In the absence of any evidence to the contrary, I would have
to say I don't know," Girling says.
SW Bohemia 1998
Out of a clear blue sky, a giant ball of ice measuring half a meter
in diameter crashed to the ground in Southwest Bohemia. After examining
pieces of the singular hailstone (which quick-thinking local residents
had rushed to their freezers), meteorologists declared that it was not
waste from passing aircraft. Scientists are at a loss to explain the incident,
especially as August is usually a slow news-month.
Más información en:
http://www.new-presence.cz/98/09/roundup.html
A Block of Ice Falls on Rue, Switzerland
Bruno Mancusi
The fall of a block of ice was observed
in Rue, Switzerland, on July 26, 1998. The author
went to the scene to write the
account of the witnesses and to take a few measurements.
The nature and origin of the block
have not been elucidated.
1. Description of the event
On Sunday July 26, 1998, at around
9h45m Central European Daylight-Saving Time
(7h45m UT), a Rue farming couple
were in front of their house when they heard a
whistling sound“like a big rocket
on August1” (Swiss national holiday). They just had time
to see a block of ice the size
of a “football” pass in front of their field of vision and crash
onto the tarred path near to their
farm. The block broke up into thousands of pieces and
the witness recuperated the largest,
which was “the size of a skittle”. The ice was “very
hard” and “snow-coloured.”
The witness estimated the weight
of the ice block at 7-8 kg and the piece that he was able
to recuperate at 6-7 kg. Unfortunately,
he did not think of conserving the block in the
freezer, and let it melt near his
house after having shown it to his neighbor, who had also
heard the noise. Thinking that
it must have fallen from an aeroplane, the witness
telephoned the Geneva-Cointrin
airport where he was advised to write to the Federal
Office for Civil Aviation (FOCA)
and send a copy of his letter to the airport. A few days
later, the witness received the
reply: the FOCA declared that it was incapable of
identifying the device responsible
because of incertitude over the time of the incident.
The witness also telephoned a journalist
from the Fribourg daily newspaper La Liberté
and a short article appeared on
July 28.
I only learned about this incident
on August 18, when a column mentioning it appeared in
Le Démocrate de Payerne.
After having found out the name of the witness, I was able to
go to the scene on September 18.
The witnesses, who were aged around sixty, seemed
credible to me and were very cooperative.
The trajectory of the block had
an azimuth of 38° (northeast to southwest) and an
elevation of 50 to 70° relative
to the horizontal. There was no abnormal radio-activity at
the point of impact or where the
witness had let the block melt, but a month and a half had
gone by, and, in the meantime,
it had rained. The layout of the place would have made a
practical joke at the witnesses'
expense difficult. On the other hand, a complete hoax
played by the witnesses is possible
(the block had disappeared), but in my opinion,
unlikely.
2. Some data
Crash site
The block of ice fell in the town
of Rue, in the Swiss Canton of Fribourg, ? = 6°49'25" E,
? = 46°37'06" N, h = 636 m.
Meteorological conditions [1]
The weather was sunny, with a temperature
of 20°C and light winds, 5 km/h, from
southwest to northeast
Altitude winds (Payerne): at 1000
m, at 23h UT of the preceding night, northeast, 30
km/h; at 11h UT southwest, 10 km/h;
at 2000 m, at 23h of the preceding night, northeast,
10 km/h; at 11h UT, southwest,
40 km/h.
Generally, there was a very leveled distribution of pressure over Switzerland.
Verification of the values estimated
by the witness: Are the size of the block and its mass
as estimated by the witness compatible
with ice (density of 0.9168 g/cm3)? To find out,
we calculated the radius of a perfect
ball of ice for different masses (Table 1).
Table 1 – Radius of a perfect ball of ice for different masses
Mass
Volume
Radius
5 kg
5454 cm3
10.9 cm
6 kg
6545 cm3
11.6 cm
8 kg
8726 cm3
12.8 cm
10 kg
10 908 cm3
13.8 cm
15 kg
16 361 cm3
15.7 cm
20 kg
21 815 cm3
17.3 cm
The witness' estimate is therefore
correct, but we notice that the radius increases little in
relation to the increase in mass
(proportional to its cube root). We therefore have the
following choice: if we base our
calculation on the mass as estimated by the witness (7-8
kg), the block should have a diameter
of around 25-26 cm. On the other hand, if we
consider the size (a football with
a diameter of 22 cm), the mass could vary between 5
and 10 kg.
3. Origin of the block
As the block no longer exists, it
is unfortunately impossible to determine its origin. It is
very unlikely that it came from
the toilets of an aeroplane as, in that case, it would have
been blue or green-coloured. Was
it a hailstone? That does not correspond with the
weather conditions. There remains
the hypothesis of an ice meteorite. Falling blocks of ice
have been reported for centuries
[2], long before the invention of aviation. Ice is
commonly found in space, it is
one of the constituents of comets and the rings of Saturn. It
is therefore not impossible for
a piece to arrive on the Earth's surface.
Falling blocks of ice are relatively
frequent. In Switzerland, the other cases that appear in
my archives are the following:
Yverdon-les-Bains (1978), Oftringen (1982), Lützelflüh
(1982), and Renens (1986). The
latter probably fell from the toilets of an aeroplane as it
was blue in colour.
It seems that the best documented
fall of an ice block took place on April 2, 1973, in
West Didsbury, Manchester, England.
The block weighed around 2 kg, and consisted of
51 layers of ice but, even in this
case, the origin was not determined [3]. A more recent
investigated fall occurred on March
23, 1995, at Yaodou, in the Zhejiang Province,
China. According to the Xinhua
News Agency, the three chunks of ice were sent to
Purple Mountain Observatory for
analysis [4]. Unfortunately, the results are unknown and
my efforts to obtain a response
from this observatory are, so far, unsuccessful.
References [1] Swiss Meteorological
Institute, personal communications, 1 October
1998.
[2] W.R. Corliss, “Tornados, Dark
Days, Anomalous Precipitation, and Related Weather
Phenomena”, The Sourcebook Project,
Glen Arm, USA, 1983, pp. 40-44.
[3] S. Welfare and J. Fairley, “Arthur
C Clarke's Mysterious World”, Collins, London,
1980, pp. 42-43.
[4] http://www.jpl.nasa.gov/s19/news56.html
and
http://www.knowledge.co.uk/frontiers/sf102/sf102g15.htm.
From: WGN, the journal of the IMO, Vol. 27, No. 2, April 1999, pp. 133-134.
(1) ICE BALLS KEEP FALLING FROM THE SKY
From Christian Gritzner <gritzner.eurospace@potsdam.com>
Hello Benny,
once again: chunks of ice falling from the sky...
Mittwoch 12. April 2000, 08:24 Uhr
Eisbrocken zerschlugen Hausdach in ?sterreich
Wien (dpa) - In ?sterreich sind Dutzende Fu?ball gro?e
Eisklumpen vom
Himmel gefallen. In K?nigswiesen nahe der Hauptstadt
Wien habe ein
Eiskoloss ein Hausdach durchschlagen und ein zwei Quadratmeter
gro?es
Loch gerissen, berichteten Anwohner. Schon in Spanien
und Italien ist
dieses Mysterium Anfang des Jahres aufgetreten. Die Polizei
vermutete,
dass die Eisklumpen sich von einem Flugzeug gel?st haben.
Best wishes,
Christian
Dr.-Ing. Christian Gritzner
EUROSPACE Technische Entwicklungen GmbH
B?ro Potsdam
Lindenstr. 6
D-14467 Potsdam
Tel.: 0331-284-3305 (FAX: -3434)
E-mail: gritzner@eurospace.de
Homepage: http://www.eurospace.de
[MODERATOR'S TRANSLATION: Reports from Austria say that
two dozen of
football-sized chunks of ice fell from the sky in recent
days. In
K?nigswiesen, near Vienna, an icy object blasted a hole,
two square
metre wide, in the roof of a house. Similar occurrances
were reported
from Spain and Italy earlier this year. Police sources
suspect that the
icy chuncks were cast off an airliner.]
================
Saludos,
-----------------------------------------
Víctor R. Ruiz
rvr@ulpgc.es
División de Comunicaciones
Universidad de Las Palmas de Gran Canaria
Salesian monastery in L’Aquila, Italy were
startled by a loud crash. Investigating the noise, they
discovered a large chunk of ice on
their patio, largely intact. Determining that it could
not have slipped off their roof and at a
loss to explain just where it came from, they called
the police. Upon examination, the
block of ice weighed in at 2 kilograms (4.4 pounds) and
no source was determined.
On the same day, about 100 miles northeast in Ancona,
Itlay, the local magistrate was
called to investigate the report of a man who was struck
on the head by a 1 kilogram (2.2
pound) chunk of ice that apparently fell from the sky.
Meanwhile, about 100 miles southeast of L’Aquila, another
similar mysterious block of ice
fell in Avellino, Italy.
El caso reciente de
Argentina
Cortesía del Dr. Rogelio Daniel Acevedo
El bloque de hielo que cayó en Mendoza, Argentina
En la primera semana de agosto de 2000, los medios gráficos y telediarios de la Argentina reportaron la caída de un bloque de hielo en la provincia de Mendoza, al Oeste del país. El evento sucedió el domingo 6 de agosto a las 14.15, en la esquina de las calles Las charcas y Martínez, de la localidad de Las Heras, próxima a la capital provincial, como relata, en la edición del 08/08/00 del periódico regional Los Andes, el señor Eduardo Carreras –de 20 años de edad- testigo presencial del fenómeno, quien ha manifestado: “Era un día totalmente despejado. Estaba yo de pie en la acera cuando sentí un zumbido muy fuerte y vi algo que venía del cielo a alta velocidad e impactó contra la calle con mucha fuerza, haciendo un gran ruido, como si fuera una explosión. Se trataba de una una bola de hielo que, al golpear contra la calzada, estalló, desprendiéndose de ella algunos trozos que volaron a una distancia de entre seis y siete metros. La masa principal de hielo era de color amarillento, en partes algo más oscuro, como engrasado y con muy mal olor. Tenía alrededor de 40 cm de diámetro, más grande que un balón de baloncesto”. Una vecina, alertada por el ruido también fue testigo secundario del suceso, como asimismo el padre del joven, Humberto Carreras. Padre e hijo preservaron el objeto en la nevera de su casa, desde donde fue recogido por personal del Centro Regional de Investigaciones Científicas y Técnicas, sito en la ciudad de Mendoza y dependiente del Consejo Nacional de Investigaciones Científicas y Técnicas, donde se lo mantuvo un tiempo bajo punto de congelamiento y se lo analizó químicamente.
Origin of Sydney fallen ice chunk a mystery
Authorities were stumped today over
the origin of a chunk of ice that crashed through the roof
and ceiling of a house on Sydney's
northern beaches.
No-one was hurt when the ice-cream
container sized block smashed apart on the bathroom
floor of a 63-year-old woman in
Coles Road, Harbord at 7.15pm (AEDT) yesterday, Manly
police said.
Hail had been ruled out and the
area was not under a flight path which accounted for the two
likely culprits, they said.
Inspector Paul Hume said the woman was home when she heard a crashing noise.
"When she looked around she saw chunks of ice on her bathroom floor."
He said police and the fire brigade found three broken tiles and a hole the ceiling.
"There was hole in the ceiling above ... three house tiles were smashed."
He said no-one was injured
and estimated the ice ball would have weighed around
one-and-a-half kilograms.
"The ice ball was the size of an ice cream container and maybe one and a half kilos," he said.
Police made inquiries with
the duty forecaster at the weather bureau who ruled out any hail
activity.
Insp Hume said the only explanation seemed to be that the ice block fell from a plane.
However, he added the area was not under a flight path.
An Airservices Australia spokesman
said it was "virtually impossible" that the ice had fallen
from a plane.
"For the ice to freeze on the aeroplane, it would have to be flying at a very high level," he said.
Samples of the ice would be tested in an attempt to establish where it came from, police said.
©AAP 2001
Flying ice block may have alien origin
17mar01
A NEW theory has emerged in the mystery surrounding a lump
of ice that fell through the roof of a Harbord home -- it could
have come from a comet.
NASA has become involved in the investigation and yesterday
sent a special container to Australia to transport the ice to
the space agency's headquarters in California.
The ice, which was 30cm long and 15cm thick, crashed
through the roof of a house in Coles Rd, Harbord, on March 6.
The lump pierced the gyprock ceiling, before hitting the
bathroom floor and shattering. Experts were not able to explain
its origin.
Dr Roger Buick, lecturer in geo-scciences at Sydney
University, was contacted by Manly police after the story ran in The Daily
Telegraph.
He contacted some former colleagues from NASA, who offered to
collect a sample of the ice for testing.
"I've worked for NASA over the years, and thought that they might be
interested in it. They're taking it to
their testing laboratory in California," he said.
"They're going to send out a specialised container to put it in, so it
doesn't get contaminated. It's currently in the freezer of the owners
of the house."
Dr Buick said because the origin of the ice could not be explained,
there was a remote possibility it was part of a comet.
"There's an outside possibility that it could be extra-terrestrial," he
said.
"As far as I know, no one's been able to get a decent sample of a
comet before.
"NASA spends billions trying to get comet tails, so they'd be
interested to see what we've got."
He agreed the mystery could not be sufficiently explained by weather
conditions or an object dropping from an aircraft.
CSIRO atmospheric researcher Paul Holper said there was no
meteorological explanation for such a large chunk of ice, which was too
large to be a hailstone.
A suggestion the ice may have come from a plane flying over the
northern beaches was discounted by Airservices Australia, a
spokesman saying it is `virtually impossible'.
Last week, physics expert Greg Skeoch said the ice may have been
travelling in excess of 200km/h before it hit the house.
NASA operates a program to examine asteroids, meteors and comets
in space, in an attempt to find out their composition and origin. Deep
Space One, launched from Cape Canaveral in October 1998, employs
the latest technology to examine dust and vapours in asteroids and
comets as they travel through the solar system.
It will next come into contact with a comet in September.
Once the sample reaches NASA, the test will be straightforward.
Scientists can eliminate the possibility that the ice came from an
extra-terrestrial source if they find earthly content within it. These
could be materials such as sodium chloride, table salt, or gypsum,
chalk.
A similar ice chunk that fell in Meliana, Spain, last January was
discounted as a comet fragment after scientists detected these
substances in a sample.
El caso reciente de USA (17
de enero de 2002) Bloque del tamaño de medio coche
Enviado por el Prof. Hilton
Pinto, Miembro del IWGFBI (Universidad de Campinas, Brasil)
Ice chunk falls from sky onto car dealership
Thursday, January 17, 2002
BY EDWARD C. FENNELL
Of The Post and Courier Staff
Literally out of the blue, something
dropped in Wednesday that froze an employee of a West Ashley auto dealership
in his path. A chunk of ice, perhaps "half the size of a car" fell out
of the sky and ripped through the roof of a repair service area at Acura
of Charleston dealership on Savannah Highway. Authorities said late Wednesday
that samples are being tested by state officials, but for now, the source
of the frozen missile remains a mystery. The ice landed about 9 a.m., just
missing a dealership employee and causing $5,000 damage to the roof and
damage to a parked, new car, St. Andrews Fire Department Capt. Ray Gorham
said "It punched through the roof like you punch your hand through a piece
of paper," Gorham said. "It had to come from high up and had to be traveling
at a high rate of speed. It had to be a fairly large piece because
it put a 3-foot hole in the roof," he said. Acura parts and service manager
Mike Huggins had just strolled through the room when the ball of ice arrived
with a loud bang. "Another minute earlier, and I would have been right
beneath it," Huggins said. "I heard a big explosion, and as soon as I did,
some of the roof was laying on the ground." At first he thought perhaps
an air conditioning unit on the roof had exploded, but that was soon
discounted. "There was a two-and-a-half foot by three-and-a-half piece
(of ice) - a pretty big slab - on the floor, with
lots of little chunks," Huggins
said. "We saved a couple of chunks," he added. Though speculation
was that the ice was contents of a leaking aircraft toilet that became
frozen outside the plane and then fell off, Huggins said the ice seemed
clear and pure."It didn't have anodor, and it was hard as a rock.
It looked like a big hunk of ice, some clear and some white, like normal
ice would be," he said. Gorham said Acura called an insurance agent who
came to the scene and advised that a police report would be necessary.
The Charleston County Sheriff's Office sent deputies who called in
firefighters to determine if the frosty visitor contained any hazardous
material. Firefighters found no trace of a hazard but called Emergency
Preparedness Department officials who took samples to send to a lab,
Gorham said. Gorham said that by the time he and other firefighters
saw the ice, much of it had melted and it looked brownish. Huggins said
the ice became discolored as it melted and mixed with insulation,
asphalt and rocks from the roof. "I have no clue where it came from,"
Gorham said. "My best guess is that it was from the edge of a meteor."
He said he checked with FAA officials who told him there was no air traffic
in the area at that time. Huggins speculated that it's possible the FAA
would not disclose the presence of any military aircraft. Wherever
it came from, the ice has authorities and dealership employees puzzled.
"None of the guys from here, or the firefighters, police or EMS had ever
seen anything like this," Huggins said. "Lots of police and firefighters
came by just to have a look because nobody could believe that what was
being radioed out had really happened."Gorham said the incident "left us
all scratching our heads. In my 16 years of fire service, it's the strangest
thing I ever saw." Huggins discounts any suggestion that anyone aimed a
ball of ice at the dealership. "I don't think the Taliban can shoot it
that far," Huggins said.
Recogen un supesto aerolito de hielo caído del cielo en La Milana (Soria)
LA MILANA (SORIA), 28 (EUROPA PRESS)
Un supuesto aerolito de hielo caído del cielo localizado en paraje de la localidad soriana de La Milana fue recogido por los agentes del equipo del Seprona de la Guardia Civil en esta provincia, según informaron a Europa Press fuentes de la Benemérita.
En concreto, estos hechos fueron comunicados a las 11.30 horas de ayer por un vecino de la citada localidad soriana por lo que varios agentes del Seprona se trasladaron hasta el lugar de los hechos, el paraje "La Tanda".
Este presunto aerolito, un bloque
de hielo de 18 kilogramos de peso, fue depositado en una nevera portátil.
Dicho hielo será remjitido al Consejo Superior de Investigaciones
Científicas (CSIC) para su análisis.
Alemania
y Austria: Raro suceso atmosférico
Cortesía de www.euronews.net
Fenómeno meteorológico o extraterrestre? Se desconoce el origen exacto de las luces y explosiones que en la noche del sábado sembraron de inquietud el land alemán de Baviera y el Tirol austriaco. La posibilidad de que se tratara de una estrella fugaz gana fuerza.
"Fue como un relámpago, pero me dije, no puede ser porque en esta época del año no hay tormentas nocturnas. Tampoco creí que pudiera tratarse de fuegos artificiales. Fue un ruido muy extraño, como de una explosión. Como era algo raro, por si acaso preferí quedarme en la cama con mi hija pequeña", afirma una habitante de Innsbruck.
Un meteorito quizás? Una agricultora de Baviera ha entregado a las autoridades una extraña roca del tamaño de un puño. Según un meteorólogo bávaro era "como una bola de fuego que de repente se apagó, como un cohete que caía horizontal, no verticalmente, no sé".
La singularidad del fenómeno hizo que se produjeran
momentos de tensión tanto en la torre de control del aeropuerto
de Munich, como en algunas comisarias de policía de la zona, cuyas
centralitas colapsaron cientos de personas alarmadas.
Algunas referencias interesantes
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imprecisely aligned cameras. The Photogrammetric Record,
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English, M., 1973: Growth of large hail in the storm. Alberta Hailstorms, Part II, Meteor. Monogr., 14, No. 36, 37-98.
English, M., 1975: Numerical model predictions for the Alberta Hail Project, JWMA, No. 2, 43-49.
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Farley, R.D., 1987: Numerical modelling of hailstorms
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photography: An example of the use of high-speed techniques
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Lozowski, E.P., and G.S. Strong, 1978: On the calibration of hailpads. J. Appl. Meteor., 17, 521-528.
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Lozowski, E.P., R. Erb, L. Wojtiw, G.S. Strong, R. Matson,
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intercomparison experiment. Atmosphere-Ocean, 16, 94-106.
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Pakiam, J.E., and J. Maybank, 1969: A preliminary survey of some lightning-hailstorm relationships. Atmosphere, 7, 131-143.
Pakiam, J.E., and J. Maybank, 1975: The electrical characteristics
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Paul, A.H., 1969: An analysis of surface hailfall reports in southern Alberta. The Albertan Geographer, 5, 44-54.
Paul, A.H., 1973: The heavy hail of 23-24 July, 1971 on the Western Prairies of Canada. Weather, 28, 463-471.
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Petersen, T.A., 1975: An analysis of thirteen years of commercial hail suppression in Central Alberta. JWMA, 7, 153-170.
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b) Papers in Conference proceedings
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crop damage and their usefullness in measuring surface hailfall, 4th
WMO Scientific Conf. Weather Modification, Hawaii, Aug.
1985, 9 pp.
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c) Scientific reports
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1983: Ground generator assessment project 1982 project
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Stone, R., and J. Warburton, 1984: Final Report for the
1983 Alberta Cloud particulate chemistry program. Desert Research
Institute, Reno, Nevada, 41 pp. + 3 Appendices.
Synoptic Patterns and Environmental
Conditions Associated With Very
Large (4" and Greater) Hail Events
Kevin L. Polston
National Weather Service
Kansas City, Missouri
ABSTRACT
I. Introduction
For the purpose of this paper, significant
hail events will refer to those situations that had 4 inch diameter hail
or larger.
Significant hail events are a threat
largely to property and agriculture, especially through the nation's heartland.
Each year
millions of dollars worth of damage
is caused by these vicious storms. While smaller hailstones can do damage
it is these large
hailstones which inflict the most
damage and are the greatest threat to property, agriculture, and even life.
For the meteorologist,
anticipating these significant
hail events can be a challenge. A climatology of these large hail events
has shown the area most at
risk is the high plains, stretching
from North Dakota to Texas. There is a distinct western edge, delineated
by the Rocky
Mountains, and on the east by approximately
95W longitude. There are scattered reports east of the Mississippi River
but in
any one year these total to perhaps
4 or 5 reports at most and are usually isolated.
A necessary ingredient, obviously,
for the development of large hail is a strong updraft. A primary conributor
to a strong updraft
is thermal buoyancy (positive area)
for lifted parcels. Updraft strength by itself, however, is not a sufficient
indicator that large
hail will develop. Hail development
and size attained appear to be greatly affected by storm scale wind structures
(Nelson,
1983). Both synoptic patterns discussed
in this paper and environmental conditions preceding the development of
large hail
events are consistent with environments
favorable for supercells. The underlying premise then is that most of the
large hail
events come from supercells.
It is interesting to note that during
the 38 year period of 1955-1993, a large increase in the number of4 inch
hail reportsbegan in
1980, the same year the National
Weather Service (NWS) began verifying warnings. While work done by Hales
(1993) and
Sammler (1993) has shown that the
number of small hail reports has increased dramatically since verification
began, one would
think that these significant hail
events would not be so affected by the verification process. This apparently
is not the case.
Better spotting and increasing
population might account for a small increase in the number of reports,
but it appears more than
coincidental that there should
be such a difference. This assertation would lead one to speculate that
many more of these events
have gone unreported over the years.
II. Types of Patterns
Type A Pattern
There appear to be two main synoptic
patterns in which 4 inch or larger hail is reported. The first, and by
far the most common
pattern, is for the large hail
to be reported along and north (or on the cool side) of a general east-west
oriented surface
boundary. Initial development of
thunderstorms and subsequent significant hail reports are normally in the
area of strongest
warm air and Theta-E advection
on the north side of the boundary. The largest hail reports have generally
been reported near
00 UTC, plus or minus an hour or
two. This is typically when daytime heating and the resultant instability
is maximized. There
have been a few cases where the
largest and most numerous events have been in the middle of the night.
These cases are
usually associated with the development
of the plains nocturnal low level jet (LLJ). The LLJ provides a source
of convergence,
strong advection and lifting, especially
over the boundary. The Type A pattern is a prolific hail producer and when
very to
extremely unstable air ( -8 or
lower LI's) is present, then very large hail is likely.
With the enhanced shear in the vicinity
of the boundary and the high buoyancy in the Type A pattern, the character
of the
convection is usually supercellular
in nature. Weisman and Klemp (1984), Brooks and Wilhelmson(1990) and McCaul(1990)
state that numerical simulations
strongly suggest the interaction of the updraft with environmental winds
can create perturbation
pressure gradients and that the
resultant vertical accelerations contribute substantially to updraft speed.
In some instances, this
contribution may be more influential
than buoyancy in driving the updraft(Weisman and Klemp, 1984;McCaul 1990).
This Type A pattern is similar in
many respects to the synoptic pattern conducive for derechos (Johns and
Hirt, 1987).
Normally, once a derecho is in
progress, the significant hail threat has ended. The greatest likelyhood
of significant hail in a
derecho event is at the very beginning,
essentially the first few hours of development. In the July 28-29,1986,
derecho event
from eastern South Dakota to eastern
Missouri (Johns and Leftwich, 1988), the first few hours of the event were
dominated by
isolated supercells which produced
extremely large hail (up to 6" diameter). The character of the convection
is important as the
large hail events are most likely
with supercells. Once the transition in character takes place the extremely
large hail threat has
usually ended. It is important
to note that the convection developed where the strongest low level warm
air/Theta-E advection
was taking place. Given the extremely
unstable nature of the air mass, thunderstorms can develop very quickly
and start
dropping large hail less than an
hour after initial development. Therefore, once the pattern has been identified
and a threat area
determined, it is important to
monitor mesoscale events using new datasets and technologies in order for
a quick and effective
response once convection is initiated.
Type B
The second significant hail producing
pattern, which is less common than the Type A pattern, is for large hail
events to occur
along and just ahead of the dryline.
The pre-storm environment consists
of extremely unstable air (-8 LI's or lower) in advance of the dryline,
surface dewpoint
temperatures at least in the low
60s east of the dryline, and ample dynamics approaching from the west.
A common feature of
the air mass in the Type B situation
is for a very dry layer of air (elevated mixed layer) overlaying the moist
air. This creates a
convectively (potentially) unstable
air mass that is reflected by the level of free convection (LFC) generally
between 680-720
mb with sharply decreasing Theta-E
profiles just above the moist layer. Most of the significant hail events
occur along or near
the instability/moisture gradient
and in close proximity to where the greatest coupling of upper divergence/lower
convergence is
taking place.
III. Parameter Evaluation
A. Instability
It is generally recognized that
strong updrafts are needed in thunderstorms to support large hail. For
this paper, the SELS Lifted
Index (Galway, 1956) was used as
a measure of the buoyancy of the atmosphere.
For ALL of the cases studied, there
was at least -8 LI values in close proximity to the area of large hail
reports. This supports
the theory that very buoyant air
is needed in order for large hail to fall. In the Type A pattern, the most
unstable air, as to be
expected, was along and south of
the surface boundary, although moderate instability was observed well north
into the cool
sector. The hypothesis with the
Type A pattern is that the extremely unstable air is lifted over the surface
boundary by the LLJ
and is forced to rise due to a
combination of lifting mechanisms. Usually, warm air advection is the primary
source of lift, but,
many times other factors contribute
in enhancing the synoptic scale lift. With such extreme instability of
the air mass, only a little
lift is needed to induce deep convection.
Prolonged synoptic scale lift acting in conjunction with the mesoscale
forcing from the
existing convection can maintain
very strong updrafts which are able to sustain and promote the development
of large hail.
In the Type A pattern, the large
hail occurs along and north of the surface boundary. This is the area of
most favorable wind
shear as there is pronounced turning
of the wind with height. With the increased shear acting on the convection,
vertical
perturbation pressure gradients
further enhance the updraft strength. It is likely the combination of synoptic
scale factors create
an environment favorable for mesoscale
interactions on the storm scale where the necessary updraft strength to
produce these
extremely large hailstones is maximized.
In the Type B pattern there was
typically a sharp gradient from the dryline to the most unstable air. A
strong, dynamic system
was usually approaching from the
west. In the majority of cases the low level moisture and the resultant
strong instability were
already in place. As the mid-level
cooling encroached over the moisture and instability axis, the lapse rates
were steepened
adding to the buoyancy and enhancing
the updraft potential. The primary forcing was a combination of upper level
divergence
over the dryline along with localized
areas of convergence on the dryline to initiate the thunderstorms. Once
again, given the
presence of extreme instability
the updraft strength was significantly enhanced, which gives rise to the
very large hail potential.
Vertical perturbation pressure
gradients, which were important in enhancing the updraft strength in the
Type A pattern, were a
result of pre-existing environmental
conditions. In the Type B pattern, mesoscale conditions need to be created
by deep
convection in order to produce
localized areas of enhanced updraft strength due to the vertical perturbation
pressure gradients.
Instability in the Type B pattern
was a result of steep lapse rates, an elevated mixed layer, and sufficient
low level moisture. In
the Type A pattern, instability
was strongly influenced by extreme values of low level moisture pooling
near the surface
boundary.
C. Other Parameters
Sounding data and derived indices
were taken from the SHARP workstation. Instability was obviously looked
at closely for the
19 cases. The Energy-Helicity Index
(EHI), evaluated as an individual parameter and possible forecast tool,
is a combination of
the buoyancy and shear combined
into a single parameter. The EHI can be displayed on PCGRIDDS with the
ETA model
data. The EHI has been used to
some extent to combine two parameters into one index as an indication of
supercell potential
(Davies 1993, Lapenta, 1990). The
EHI was investigated to help distinguish those environments which might
be capable of
producing supercells in conjunction
with either the Type A or Type B pattern. Since the EHI is primarily a
buoyancy/shear
parameter one of these factors
could weigh more heavily, depending on the pattern observed (or forecast).
From proximity
sounding analysis, it appears that
EHI values above 2 are a good indicator for supercells with large hail.
Fig.7 shows selected
proximity sounding parameters and
an average of those parameters associated with 4" hail events.
Proximity soundings of 4" or larger hail events
IV. Forecasting Possibilities
A. Observed Patterns
The succesful forecast of a significant
hail event is recognizing the synoptic patterns associated with these events
and observing
the strength of the parameters
involved. If they reach a minimum "threshold" criteria then the meteorologist
should anticipate a
potential event and actively monitor
the forecasted "genesis" region for initial development. Often, the thunderstorms
will
develop very rapidly and quickly
become severe, many times less than an hour after initial development.
On some occasions, a
pre-existing convective system
will move into a region that becomes increasingly favorable for renewed
updraft strength with
resulting large hail. This is typically
a nocturnal type event with the plains LLJ acting to enhance the convection.
B. Model Data
Since the patterns or parameters
investigated in this study were on the synoptic scale, using the numerical
model guidance could
give indications of when and where
the threat area would be most likely. Now that most forecast offices are
receiving gridded
data (PC-GRIDDS), actual values
of warm air/Theta-E advection can be quantitatively evaluated. Once a forecaster
has
determined if a favorable synoptic
pattern exists, then he/she can actively investigate the area using threshold
values via the
gridded data. This type of information
can be used to anticipate the potential for a significant hail event and
prepare the
forecaster to take the appropriate
actions as the time of the predicted event approaches.
VII. Conclusion
Two synoptic patterns associated
with significant hail events (>4 inches) in the climatologically favored
Great Plains have been
identified. The Type A pattern
is found to be a prolific hail producer, if extremely unstable air (-8
LI or lower) is found along
and south of a generally east-west
oriented surface boundary. The Type B pattern is normally confined to the
Southern Plains
states in the Spring and early
Summer. This pattern is associated with strong, dynamic systems moving
out of the Rockies and
interacting with the dryline. It
is hypothesized that for both patterns deep convection creates vertical
perturbation pressure
gradients, which locally enhance
updraft speed/strength within the thunderstorm. This enhancement of the
updraft would not be
likely without pre-existing environmental
conditons. These conditions always include extreme instability in place,
or poised in
position to be quickly advected
into the threat area. With nocturnal significant hail events, strong warm
air advection along with
a strong LLJ are the main lifting
mechanisms. Sometimes the extreme instability will be located above the
boundary layer or
forced to rise over the surface
boundary, as previously stated with nocturnal events, in the Type A pattern.
Over the past 15 years there has
been a rather dramatic increase in the number of 4 inch hail reports. The
NWS began
verifying warnings in 1980, when
this upward trend started. It is assumed that no meteorological shift of
weather patterns has
occurred so the verification process
has enhanced the number of reports of these 4" and larger hail events.
Since it is
reasonable to assume that these
events have been occurring long before the verification process began it
is reasonable to
assume that these 4 inch hail events
may not be isolated instances and may occur with greater regularity than
previously thought
or believed. This makes them a
significant meteorological concern. This paper has identified two main
synoptic patterns
associated with these types of
hailstorms and isolated some parameters which may help anticipate a large
hail threat.
Meteorologists should be able to
locate the general area of concern with the careful analysis of raob and
model data on the
synoptic scale and refine the area
with mesoanalysis of the many realtime data sets that are and will be available
during the
ensuing years as the time of the
event draws near. This anticipation of the event should lead to timely
warnings with greater
emphasis on the type of expected
event.
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Artículo publicado en El Mundo por Fernando López-Vera (Enero/2000)
El filón de los aerolitos
En un principio el trabajo respondía a satisfacer la curiosidad científica de un hecho sin explicación aparente y que por otra parte era objeto de una investigación judicial porque el impacto del bloque había dañado un coche. Los acontecimientos posteriores desbordaron ampliamente los objetivos iniciales.
Desde un principio la hipótesis de trabajo, fue considerar todas las hipótesis, desde el fraude a un origen cosmogénico, que aunque poco probable no se podía descartar, pasando por todas las posibilidades conocidas o desconocidas de formación en la atmósfera. Por ello no deja de sorprender el que se nos atribuya a miembros del grupo, entre los que me incluyo, o al coordinador, la defensa de ninguna hipótesis concreta.
Es comprensible la expectación creada ante el bombardeo de "aerolitos" en nuestro país, y el que se pidan explicaciones rápidas de este hecho. Explicaciones que no podemos ofrecer hasta que no dispongamos de datos fiables en cuya obtención trabajamos. Sin embargo ante la presión de la demanda social de una explicación rápida, se produce la comparecencia de numerosos científicos ante los medios de comunicación, que alimentan aun las especulaciones sobre este asunto.
El grupo de trabajo que investigamos la caída de "aerolitos", se ha mantenido en contacto con todas las personas e instituciones implicadas y su trabajo ha consistido en el seguimiento de las caídas y hallazgos y la realización de los trabajos de campo. Hemos establecido una metodología de trabajo rigurosa, de la que se ha dado conocimiento a la opinión pública a través de un comunicado del Consejo Superior de Investigaciones Científicas, leído y distribuido a los medios por la Dra. Pilar Cantó, Directora del Instituto del Frío, el Martes día 18. Se ha realizado un muestreo de los bloques siguiendo un protocolo establecido previamente y enviado a los laboratorios el día 19, para su análisis químico e isotópico, procurando la aplicación de la mejor tecnología analítica disponible.
Los objetivos que se persiguen es hacer una primera identificación de las muestras para dar una respuesta a la demanda de la opinión pública de una explicación. Si procede, se aplicará a continuación el plan de trabajos establecido, cuyos resultados finales no se obtendrán hasta dentro de varios meses.
Fernando Lopez-Vera
Catedrático de Hidrogeología
de la UAM
Miembro del grupo de trabajo para
el estudio las caídas aerolitos
Artículo publicado en El Mundo por Jesús Martínez-Frías (Enero/2000)
Un caso excepcional
La caída de bloques de hielo durante los últimos días en España es, como ya se ha apuntado en multitud de medios, un hecho totalmente excepcional. Es cierto que una buena parte de los ejemplares constituyen simples fraudes, errores o excesos de celo, debidos al interés por este fenómeno. Pero no es menos cierto que disponemos de, al menos, 9 caídas perfectamente verificadas, que han tenido lugar en tan solo 5 días, y que han generado —como consecuencia del impacto— algunos desperfectos en naves industriales, automóviles, o que se han producido delante de testigos. Dada la baja probabilidad de que esto ocurra en la naturaleza con tal abundancia y periodicidad, desde el primer momento se consideró interesante investigar qué es lo que realmente estaba sucediendo, de acuerdo con un plan de trabajo desde una perspectiva multidisciplinar.
No se descartó ninguna hipótesis a priori hasta que se dispusiera al menos de los primeros datos, y actualmente ya se ha ofrecido una caracterización textural, hidroquímica e isotópica preliminar de las muestras y una gradación de las hipótesis de trabajo. Ello ha permitido definir la heterogeneidad química y el carácter meteórico de las aguas, así como descartar que éstas procedan de residuos de aeronaves, que los bloques de hielo puedan definirse como aerolitos, o cualquier variante tipológica de meteoritos y que su formación se deba a un proceso atmósférico como los que usualmente se desarrollan en la troposfera.
La interpolación de los resultados obtenidos permite: 1) plantear como poco probable una génesis ligada a procesos de condensación de hielo en aeronaves o bien de tipo cosmogénico, de acuerdo con los planteamientos sobre minicometas de Frank y Sigwarth y 2) proponer una hipótesis más consistente con los datos obtenidos hasta el momento, según la cual la formación de los bloques de hielo se debería a un proceso natural, terrestre, muy inusual, en las capas altas de la atmósfera, aún teniendo en cuenta la escasez natural de vapor de agua en la estratosfera y que no se conozca un mecanismo preciso de formación. En el pasado no muy lejano existen varias referencias de caídas de bloques de hielo de 30 cm en 1811, en Derbyshire, de casi 1 kg. en New Hampshire, en 1851, de 2 kg. en Texas, en 1893, y otras recientes como las de provincia de Zhejiang (China) en 1995 (bloque de 1 m de diámetro) o la de Campinas (Brasil), en 1998, (dos bloques de hielo de 200 y 50 Kg.).
Se trata sin duda, de un problema científico de gran interés, con múltiples implicaciones, e investigadores e instituciones de distintas partes del mundo han ofrecido ya su colaboración para participar en sucesivos estudios, tanto isotópicos como de caracterización de propiedades termodinámicas y estructurales. Por ello, se planea la ampliación del Grupo de Trabajo mediante la incorporación de expertos en las distintas áreas científicas. Sólo huyendo de la estéril especulación sin datos, y abordando estos estudios con el máximo rigor científico, podremos resolver la génesis de los bloques de hielo caídos del cielo.
Jesús Martínez-Frías
Coordinador de la Comisión
