What Is a Horseshoe Cloud? Viral Photo Captures Rare Phenomenon

A rare cloud formed over Nevada Thursday and one onlooker got a photo of the mysteriously-shaped phenomenon. The National Weather Service in Elko, Nevada, posted a photo of the cloud to Twitter and thanked Christy Grimes for taking the photo.

The cloud looks exactly like what its name would suggest. Three sides of a horseshoe set on a background of other clouds.

One of the rarest clouds ever. This was taken over Battle Mountain, Nevada, USA on 8 March 2018.

It's called a horseshoe cloud for obvious reasons. #nvwx

Credit goes to eagle-eye Christy Grimes. pic.twitter.com/XgQDY77ZzM

— NWS Elko (@NWSElko) March 9, 2018

Twitter users were confused by the photo of the cloud and couldn't help but bring up the idea of possible alien involvement. But the NWS Elko took to Twitter to explain the cloud. The cloud is formed through a process involving the movement of the wind.

How does the horseshoe cloud form... (previous tweet) as the updraft pushes flattish cumulus clouds up & a horizontal vortex develops from differential updraft speeds...

— NWS Elko (@NWSElko) March 9, 2018

Continue. (from previous tweet)...As the vortex climbs, it's caught in the faster horizontal winds aloft,& the middle part of the vortex catches the faster speeds with the ends being slower #nvwx

— NWS Elko (@NWSElko) March 9, 2018

Essentially the cloud forms in a vortex, or an area of spinning air. This is what forms a cyclone or a tornado, when that happens the vortex is vertical. When it forms horizontally, it forms a sort of crescent cloud, according to the Cloud Appreciation Society.

There are various stories about the luck the cloud brings or doesn't bring to those who see it. Some people think when the cloud is turned down, as it appeared in Nevada, it drops luck on those down below, according to the Society.

Twitter users thought the cloud looked a little different than a horseshoe. Some thought it looked like a mustache floating right in the middle of the sky.

Pretty sure that’s a floating mustache https://t.co/5P4bHXc5Av

— Beks (@ShmeckaBeks) March 10, 2018

Others thought it looked more like a staple for paper than a horseshoe.

Horseshoe?? I know a staple when I see one, son. https://t.co/tMMv4r2XxB

— what is dog?? (@semisponge) March 10, 2018

One user even took the opportunity to explain the cloud using a small drawing and explained it as a "weak & sideways cousin of a waterspout or tornado," said user Mika McKinnon.

Q: What is even happening?!
A: Horseshoe clouds are partially-visible vortices. An updraft hit a sheer layer, getting knocked into a spin & flattened.

Oversimplifucation: It's a very weak & sideways cousin of a waterspout or tornado, a quickly-dissipating shred of cloud. pic.twitter.com/S9pWeqrc2y

— Mika McKinnon (@mikamckinnon) March 9, 2018