FALLSTREAK CLOUDS

This odd phenomenon causes a circular hole to appear in an otherwise normal cloud layer

SUPERCOOLED CLOUD

Temperatures are below freezing, but the water droplets remain liquid due to a lack of ice nucleation particles.

CLOUD FREEZES

When ice crystals start to form, they set off a domino effect in which more and more water freezes.

A HOLE IS CREATED

When the ice crystals are big enough, they begin to fall as snow, leaving a big hole in the cloud.

Unusual cloud formations, such as these lenticular clouds, may cause some UFO sightings