[meteorite-list] Mysterious chunks of ice pelt Iowa town

From: Mike Groetz <mpg444_at_meteoritecentral.com>
Date: Fri, 27 Jul 2007 10:25:42 -0700 (PDT)
Message-ID: <224441.83245.qm_at_web32905.mail.mud.yahoo.com>

There are some pretty good pictures on the CNN site.
Everyone keep their head down....
Mike

http://www.cnn.com/2007/US/07/27/falling.ice.ap/index.html

Mysterious chunks of ice pelt Iowa town
Story Highlights
One falling chunk of ice reportedly weighed 50 pounds

No one on the ground hurt by falling chunks of ice

Possible sources of ice: Airplane or a thunderstorm

DUBUQUE, Iowa (AP) -- Large chunks of ice, one of them
reportedly about 50 pounds, fell from the sky in this
northeast Iowa city, smashing through a woman's roof
and tearing through nearby trees.

Authorities were unsure of the ice's origin but have
theorized the chunks either fell from an airplane or
naturally accumulated high in the atmosphere -- both
rare occurrences.

"It sounded like a bomb!" 78-year-old Jan Kenkel said.
She said she was standing in her kitchen when an ice
chunk crashed through her roof at about 5:30 a.m.
Thursday. "I jumped about a foot!"

She traced the damage to her television room, where
she found a messy pile of insulation, bits of ceiling,
splintered wood and about 50 pounds of solid ice.

Karle and Mary Beth Wigginton, who live a block away,
heard a loud "whoosh" coming through the trees. They
discovered several large chunks of ice in front of
their home and some smaller ones in the yard and in
the street.

"I could see where branches were shredded, which told
me it was definitely coming out of the sky," Karle
Wigginton said.

He estimated the original chunk of ice was the size of
a basketball. "It was pure white," he said. "The main
parts I picked up were very smooth."

Elizabeth Cory, a spokeswoman for the Federal Aviation
Administration, said investigators would contact
Kenkel to try to determine the source of the ice.

"It is very uncommon for something like this to come
from an aircraft," Cory said. "That is really unusual
if it is pure white ice, especially at this time of
year."

Occasionally, aircraft latrines discharge contents at
altitude, resulting in chunks of descending ice.
Airplanes also sometimes accumulate ice on their edges
in certain atmospheric conditions, including high
altitude and extreme moisture, said Robert Grierson,
the Dubuque Regional Airport manager and a pilot.

The moisture involved in such a scenario could have
come from the tops of strong thunderstorms. However,
Dubuque had clear skies at the time the ice fell, said
Andy Ervin, a meteorologist with the National Weather
Service in Davenport. "There was nothing unusual going
on," he said.

David Travis, a professor of geography and geology and
an associate dean at the University of
Wisconsin-Whitewater, has studied the phenomenon of
large chunks of ice falling from a clear sky. He said
it's possible the ice could have been a megacryometeor
-- "similar to a hailstone, but without the
thunderstorm."

Travis is part of a research team that has documented
more than 50 possible megacryometeor cases during the
past five years. Some involve ice chunks the size of
microwave ovens.

"It is hard to keep something like that suspended in
air without a thunderstorm," Travis said.

Most megacryometeor sightings have occurred in coastal
areas, where atmospheric turbulence helps keep ice
suspended long enough to grow into large chunks.

Travis' research team speculates the phenomenon could
be linked to global warming, suggesting that climate
change might make the tropopause portion of the
atmosphere colder, moister and more turbulent.

"But those don't typically happen in the summer time,"
Travis said. "It seems like they are mostly associated
with the passage of passing cold fronts."







       
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Received on Fri 27 Jul 2007 01:25:42 PM PDT