DENVER (CBS4) – Did you see the really cool, spiral-shaped cloud hovering along the Front Range early Wednesday afternoon? It was quite the talker on social media and while it’s hard to say what caused this cool cloud I do have two theories.

Theory #1

There’s a good chance that it was originally a jet contrail that became twisted and reshaped by atmospheric wind. When I posed this theory to several who live in the area they said they were confident there was no jet traffic overhead at the time.

But keep in mind a contrail at this altitude would not have been created by a plane flying into or out of Denver. It would’ve been created by a flight at cruising altitude passing high over the Front Range.

Helix Cloud

(credit: John Mele)

Also, if this cloud was the result of a contrail, it wouldn’t have necessarily formed directly overhead. It could have been from a plane that was several miles away and it drifted into the region, constantly being twisted and reshaped by wind at that altitude.

Theory #2

If it wasn’t an old jet contrail being reshaped by the wind then my next best guess is something along the lines of a lenticular cloud mixed with the conditions that create a Kelvin–Helmholtz wave cloud. Essentially there was enough moisture at that altitude to create a cloud, but the stability of the atmosphere was such that it could only grow to a shallow depth.

Helix Cloud

(credit: Mike Van Portfliet)

Add in a lot of wind shear between the bottom and the top of the cloud, which is a change of speed or direction with height, and the air was essentially rotating on a horizontal axis, making the cloud have a cool spiral, or helix shape.

While it’s nearly impossible to say for sure, it’s fun to think of possible causes. We are so lucky to live in such a beautiful state and in the shadow of mountains that interact with our atmosphere, giving us so many cool things to see in the sky.

Cool, spiral-shaped cloud over the Flat Irons on Wednesday. (credit: Mike McNaughton)

Chris Spears

Comments (2)
  1. Delsol Losled says:

    Well, geoengineering is the answer. There is nothing natural abut this formation, you can throw your theories into the bin and start educating yourself on the matter. You will thank me later.

    1. Kurt Juergens says:

      Exactly right you are.