Thursday, November 21st 2019, 6:04 pm - Looks eerie, but there's a completely rational scientific explanation.
Numerous sightings of these bizarre clouds floated all over social media on Thursday. No, they're not caused by U.F.O.s, but there's a plausible explanation.
From Nanaimo to Duncan, these fallstreak holes -- a large circular gap in the clouds --developed shortly after 10:30 a.m. local time on Thursday.
Spotted this unusual cloud today over Duncan/Crofton this morning. Definitely some ice crystals and downward air movement involved. Any guesses what this is?@JWagstaffe @50ShadesofVanBurkeville Mama on Twitter
After some meteorological detective work, planes are normally the cause of these rare hole-punch clouds.
But, what flight(s)?
Sure enough, just after 10:00 am, Westjet flights 1876 and 1872 took off at Vancouver International Airport within a couple of minutes of each other, Destination: Hawaii.
The flight paths below show the planes ascending above 5,000 meters across southern Vancouver Island, near the height where altocumulus clouds are lurking, awaiting their transformation into the miraculous fallstreak hole.
I won't bore you with the details, but if you want some more, our science writer Scott Sutherland covered this right here.
In essence, there's an immense amount of supercooled water droplets high up in the atmosphere, all waiting to freeze. For that, an ice nucleus is necessary to start the chain reaction to precipitate. The wings and engines can trigger this process, along with a heat generated from the freezing process. Then, the water droplets begin to evaporate creating the ever-growing void.
But, it gets better. We hit the fallstreak jackpot, which also featured a rainbow.
This photo above illustrated the ice crystals that form, and were refracted just so, to produce a mini-rainbow, almost resembling a sun dog, a type of atmospheric halo.
So, if you knew any family members on those WestJet flights, thank them for the beautiful meteorological display.