Fallstreak hole

A fallstreak hole (also known as a cavum, hole punch cloud, punch hole cloud, skypunch, cloud canal or cloud hole) is a large gap, usually circular or elliptical, that can appear in cirrocumulus or altocumulus clouds. The holes are caused by supercooled water in the clouds suddenly evaporating or freezing, and may be triggered by passing aircraft.

Fallstreak hole (Cavum)
Fallstreak hole over Austria
Abbreviationcav
GenusCirrocumulus , Altocumulus , Stratocumulus
VarietySupplementary feature
Altitude500-15,000 m
(2,000-49,000 ft)
AppearanceHole in the clouds
PrecipitationVirga

Because of their rarity and unusual appearance, fallstreak holes have been mistaken for or attributed to unidentified flying objects.

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