Ask the Meteorologist: How do dust devils form?

Saturday afternoon, the Mt. Juliet League Inc. out of Tennessee posted a wild video of a dust devil to its Facebook page.

The video is incredible. And - at least in this part of the country - these seem to happen often near baseball and softball fields, right?

Let's talk about how they form, which might explain why the diamond is the destination for dust devils!

How do dust devils form?

No, the Tazmanian Devil from Looney Tunes has no role in this. Sorry for the bummer!

The first and most important step is heating the surface.

You often see dust devils on clear, blue sky days. That's just one thing that separates a dust devil from a tornado, even though they look alike.

The temperature differential causes a very tiny area of low pressure to develop. Air rises near the center of low pressure.

Air also rushes toward the area of low pressure to essentially "fill the void." In the Northern Hemisphere, that air will then spin counter-clockwise.

As the air rises, cools and condenses into a cloud, you get the dust devil to form from the ground up.

In its "mature" stage, it looks like this still image that I grabbed from Mt. Juliet League Inc.'s video.

Cooler air eventually chokes off the circulation.

In the case of the video above, this happened when the dust devil moved from the dirt on the infield to the grass on the outfield. That outfield grass is significantly cooler than the lighter-colored dirt in direct sunlight.

When/where do dust devils happen most?

A 2015 study attempted to show where these happen most often, as well as the months and time of day when they happen.

It's no surprise that these happen most often around the middle of the day. This is when the sun is at its highest, and (therefore) the incoming solar radiation is highest.

The study also shows how frequently these happen during the spring and summer months in the Northern Hemisphere.

It should also be no surprise, then, that these happen most often in desert regions. Specifically, it states that the "Atacama and Sechura Deserts of South America and the land areas surrounding the Red Sea" are the parts of the world that see dust devils most often.

In the U.S., the Desert Southwest and Four Corners regions see dust devils most often. However, if it is hot and dry enough, you can see them outside of that.

Have questions about the weather and how it works?

Send me an email with the subject line 'Ask the Meteorologist:' to cmichaels@wral.com.