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.

See all of the best photos of the week in these slideshows

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.

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.

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

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.