Yesterday, Pam Spicer was admiring the clouds when she noticed a hole in the clouds! It looked like someone had punched a hole in a layer of clouds out over the Northumberland Strait between Cape Tourmentine New Brunswick and Borden PEI. This unusual yet beautiful sight has a name and can be explained…
A fallstreak or hole punch is a large circular gap that can appear in the clouds; most often in high clouds like cirrocumulus or altocumulus.These holes are formed when the water temperature in the clouds is below freezing but the water has not yet frozen, due to the lack of ice nucleation; these drops are known as super-cooled. With ideal conditions, the water droplets around the crystals will evaporate, leaving a large, often circular, hole in the cloud.
Aircraft climbing through the air can trigger this process. As the plane gains altitude, it punches through the cloud layer of super-cooled water droplets stretched across the sky leaving behind a hole. It reminds me of the sheet of dough stretched across the counter when mom was cutting out her famous cake doughnuts. I digress...
Depending on the amount of moisture in the air, one of two things can happen.
1) It can snow: Ice particles grow at the expense of the super-cooled water droplets and fall out as snow. The snow changes to rain on its way down to earth.
2) Or a hole remains in the sky: if the cloud layer is thin or if the water is not replenished, the snow leaves a hole in the cloud.
Scientists first reported observing hole punch clouds in the 1940’s. They often lead to false reports of UFOs or rocket launches.
Another good reason to look up and admire Mother Nature’s handy work!