Megacryometeor

A megacryometeor is a very large chunk of ice which, despite sharing many textural, hydro-chemical, and isotopic features found in large hailstones, is formed under unusual atmospheric conditions which clearly differ from those of the cumulonimbus cloud scenario (i.e. clear-sky conditions). They are sometimes called huge hailstones, but do not need to form under thunderstorm conditions unlike hailstorms. Jesús Martínez-Frías, a planetary geologist and astrobiologist at Institute of Geosciences (Spanish: Instituto de Geociencias, IGEO) in the Spanish National Research Council (Spanish: Consejo Superior de Investigaciones Científicas, CSIC) in Madrid, pioneered research into megacryometeors.