is a very large chunk of ice
, which, despite sharing many textural, hydro-chemical and isotopic features detected in large hailstones, are formed under unusual atmospheric conditions which clearly differ from those of the cumulonimbus clouds
scenario (i.e. clear-sky conditions). They are sometimes called huge hailstones
, but do not need to form in thunderstorms
. Jesus Martinez-Frias, a planetary geologist of the Center for Astrobiology in Madrid pioneered research on megacryometeors in January 2000, after ice chunks weighing up to 6.6 pounds rained on Spain out of cloudless skies for 10 days.
More than 50 megacryometeors have been recorded since the year 2000
. They vary in size between 0.5 kg to over 200 kg. One was measured in Brazil
as 220 kg.
The process that creates megacryometeors is not fully understood. They may have a similar mechanism of formation as hailstones
, and have been recorded falling out of the clear sky in the summer. Analysis of megacryometeors show that their composition matches normal rainwater
for the areas in which they fell. It is known that they do not come from airplane toilets because the large chunks of ice that occasionally do fall from airliners are distinctly blue due to the disinfectant used. In addition there are many events which occurred prior to the invention of the aircraft. First results indicate that fluctuations in tropopause
, associated with hydration of the lower stratosphere and stratospheric cooling, can be related with their formation. They are sometimes confused with meteors
because they can leave small impact craters.
- Megacryometeors: Resource Site
- News Report: Ice Chunk Hits Oakland, CA, USA
- News Report, July 8, 2006: Ice Chunk hits South Africa
- Megacryometeors: fall of atmospheric ice blocks from ancient to modern times
- The Peculiar Phenomenon of Megacryometeors
- Sandton ice ball fell out of clear sky, says scientist
- Megacryometeors: Scientific article (Hydrochemistry and isotopic composition), Journal of Atmospheric Chemistry, 2005
- Megacryometeors: Scientific article (Distribution on Earth, AMBIO: A Journal of the Human Environment, 2006
- Huge chunks of falling ice mysteriously pelt Iowa neighbourhood, smash roof
- Getting to the truth of falling ice chunks, Chemical Sience, Katherine Davies, 2008
- Monitoring the fall of large atmospheric ice conglomerations: a multianalytical approach to the study of the Mejorada del Campo megacryometeor, Journal of Environmental Monitoring, 2008
- What Causes Megacryometeors?
- The problem of Ice Meteorites, Martin Beech