July 27
Dubuque, Iowa — Large chunks of ice, one of them reportedly about 50 pounds, fell from the sky Thursday in this northeast Iowa city, smashing through a woman's roof and tearing through nearby trees.

Authorities are 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.

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.

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," he 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 with global warming, suggesting that climate change might make the tropopause portion of the atmosphere colder, moister and more turbulent.
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how many Confirmed "naturally formed megacryometeor's" have there been?
I don't know of any, yet ( http://en.wikipedia.org/wiki/Megacryometeor says many events prior to aircraft, but only link I found on that was a reference to tunguska?? )
but I have heard of it coming from airplanes... past 5 years, aging planes, coastal areas...
first report I see is from 2000, the rain in spain falls mainly off the plane

This is toooooo weird. My mother-n-law just emailed me from Dubuque, Iowa. The house the basketball sized ice that broke through the roof and into a room of the house is one of her dear friends!!! She said her friend is okay. But WTF?????

Gee, I'm so glad we just got a metal roof. But during a severe lightning storm recently, one of my neighbors said "We've got a lightning storm and we've got metal roofs?????" Well, I guess the metal roofs are to protect us from all the large heavy trees in the neighborhood, trees that have known to come crashing through a roof.

Sheesh, you just can't win, can you?