How to identify a shelf cloud. They aren't as dangerous as you might think

As Des Moines was hit with strong thunderstorms Tuesday, pictures of a "shelf cloud" start circulating social media.

The images displayed what looked like low hanging clouds under more cloud coverage that effectively blocked out most sunlight mid-Tuesday morning. While the images are striking, what actually is a shelf cloud and did the people of Des Moines catch one looming amid thunderstorms?

Did Des Moines see a shelf cloud Tuesday?

Yes, a shelf cloud was seen over Des Moines Tuesday, according to the National Weather Service. It was accompanied by a short-term thunderstorm.

What is a shelf cloud?

A shelf cloud can appear on the line of a series of storms, similar to what Des Moines saw Tuesday morning, said Dylan Dodson, a meteorologist with the National Weather Service.

It typically occurs from the air ahead of the storm meeting with the cool air that comes with the rain within the storm. This creates a slanted approach to the clouds.

"It can be very interesting as that comes through," Dodson said. "It's often mistaken for tornadoes when often there are not any tornadoes associated with it."

What weather conditions are shelf clouds associated with?

With linear storms, also known as squall lines, shelf clouds are fairly common. Squall lines often pass quickly and are less prone to produce tornadoes, according to the National Severe Storm Laboratory .

How to identify a shelf cloud?

Shelf clouds are usually confused with wall clouds. Wall clouds develop under supercells which consist of storms that are rotating. Wall clouds can be a precursor to tornadoes.

"Wall clouds are typically a horizontal rotation," Dodson said. "So they are moving in a circle essentially."

Shelf clouds are different because they are more vertical motion. They are larger and lack horizontal rotation which can form a tornado.

Kate Kealey is a general assignment reporter for the Des Moines Register. Reach her at kkealey@registermedia.com or follow her on Twitter at @ Kkealey17 .

This article originally appeared on Des Moines Register: How to identify a shelf cloud. They aren't as dangerous as you might think