At around 1pm on Monday in Wonthaggi, 82 miles south east of
Melbourne in Victoria, the blue limitless sky with specks of cloud looked like
it had a massive hole in it – with a gleaming rainbow-like pattern in the
middle.

Bureau of Meteorology forecaster Adam Conroy explained the phenomenon, saying
fallstreak holes are gaps that appear in high clouds when a section of the cloud
freezes.

These ice crystals then become so heavy they fall out of the cloud, leaving what
looks like a massive hole.

These holes form in clouds when water droplets start to freeze – the temperature
drops below 0°C but is not yet frozen. These water droplets need a tiny
particle, known as the ice nucleus, to freeze at a temperature below -40°C.

Once the ice crystals are formed, it sets off a domino effect which causes water
droplets around the crystals to evaporate in a phenomenon known as the Bergeron
process. This leaves a large, sometimes circular-shaped hole in the cloud.

Thanks to Ron Gleason