Wonthaggi ‘hole-punch’ cloud looks pretty, and strange

5 Nov 2014

Hole-punch cloud by Peter Fell, via ABC News (Australia)

A rare ‘hole-punch’ cloud was spotted above an Australian town earlier in the week, and it just looked so weird.

Residents of Wonthaggi spotted the bizarre cloud formation on Monday, with images subsequently going viral.

Hole punch clouds are created when the centre of a cloud formation literally falls out, usually the result of an incredibly acute and localised snowfall.

For example, look at the image of this hole-punch cloud and picture the centre still being there. What happened, for some reason, was the temperature in the middle dropped significantly, forming heavier clusters of snow, thus falling away.

“Refraction of sunlight by the ice crystals results in the rainbow, while the arrangement of those crystals gives us a bright patch of light in the middle called a sun dog,” according to National Geographic, which explains the process in detail here, theorising that airplane propellors could be the cause of some hole-punch formations.

Pic of hole-punch cloud from David Barton, via ABC News (Australia)

Ironically enough Gregory Thompson, a scientist at the National Center for Atmospheric Research, notes how it could well be researchers themselves creating these spectacles.

“[Researchers] spend an awful lot of time flying through clouds to collect data, which we use to build models that mimic natural clouds. We may be altering that data as we measure it,” he says.

“It’s not a big effect, but it’s something to be mindful of in future atmospheric modeling.”

Either way, it looks both weird and cool at the same time.

Gordon Hunt was a journalist with Silicon Republic