Many on Vancouver Island had their cameras out early Monday morning for a phenomenon in the clouds.
A fallstreak hole, or a “hole punch cloud”, could be seen on the Island at sunrise, with a large circular or elliptical gap appearing in the clouds.
The U.S. National Weather Service says fallstreaks develop as “high to mid-level clouds, such as altocumulus, are often composed of tiny water droplets that are much colder than freezing, but have yet to freeze.”
On Twitter Monday, scientist Ed Wiebe of the University of Victoria said the “supercooled liquid water in the clouds rapidly changes to ice because of a disturbance near the centre of the hole. the disturbance spreads.”
Three views of the same phenomenon, three and thirteen minutes after the first image. This is a fallstreak hole. Supercooled liquid water in the clouds rapidly changes to ice because of a disturbance near the centre of the hole. The disturbance spreads.#UVic #VictoriaBC 1/3 pic.twitter.com/jesDMCVTJy
— Ed Wiebe (@edwiebe) January 28, 2019
“A quirk of water and air means that water vapour condenses more readily on the ice than it did on the water. The ice crystals grow rapidly, drying the air and falling out of the cloud. This leaves a clear hole in the cloud layer with a fallstreak below it,” Wiebe posted.