Tornadoes, Landspouts, Waterspouts & Dust Devils - What's The Difference?

By: Chief Meteorologist Chris Yates, AMS Email
By: Chief Meteorologist Chris Yates, AMS Email
The difference between Tornadoes, Landspouts, Waterspouts and Dust Devils.

A large tornado near LA Grange, Wyoming on June 5th, 2009.

The Definition of a Tornado

A tornado is a violently rotating column of air extending between, and in contact with, a cloud and the surface of the earth.

For someone to understand the difference between Tornadoes, Landspouts, Waterspouts and Dust Devils, they need to understand the definition of a tornado. Now, lets break down each individually!

Tornado

(Image 1)

A tornado is a violently rotating column of air extending between, and in contact with, a cloud and the surface of the earth.

Most tornadoes form within rotating thunderstorms called Supercells with mesocyclones. These extend from the cloud and move down to the ground. These Tornadoes can do significant damage and have winds speeds over 299 MPH!

Landspout

(Image 2)

By definition, a Landspout (once known as "Dust Tube Tornadoes") is just a type of tornado. It is a violently rotating column of air that is in contact with a cloud and the surface of the earth. What makes this different than the "typical" tornado, is how it develops and what it is attached to. Unlike the Supercellular Tornadoes, it does not move from base of the cloud to the ground. It actually develops near the surface and works it's way up.

Landspouts form when boundaries merge near a developing thunderstorm. As these boundaries collide, the air will sometimes swirl. This swirl may happen on the ground or a couple hundred feet above the ground. If this swirl moves under a developing thunderstorm, the swirl may be ingested in to the storms updraft stretching and therefore tightening the swirl. Once the swirl is in contact with the cloud while in contact with the ground it is given the name "Tornado". These tend to take on more of a tubular appearance as opposed to a wedge, cone or rope like appearance.

Landspouts tend to be weaker then those formed from Supercells, most being rated an EF0. However, a few have been know to produce EF3 damage. Landspouts also tend to develop more in the high plains, such as SE Wyoming, due to a drier climate. The dry air makes it harder for Supercells to have low enough cloud bases to form large Tornadoes.

Waterspouts

(Image 3)

There is nothing special about a Waterspout, it is a Tornado. It doesn't matter if it forms from a Supercell or a developing thunderstorm, as long as the tornado is over water it is known as a Waterspout.

Dust Devils

(Image 4)

These whirlwinds tend to develop in hot and dry environments. These form when hot air rises through pockets of cooler air above the ground. Sometimes, this rising column of air can begin to rotate if environmental conditions are right. As the air rises, the vortex will tighten and spin faster. As the whirlwind spins, it will bring in more hot air which will keep the air rising allowing these to be self sustaining making them long lived.

Unlike Landspouts, Dust Devils are not in contact with the base of a developing thunderstorm. This lack of additional lift from a thunderstorm's updraft will usually keep the whirlwind much weaker than a Landspout.

Image 1

Tornado (Photo By Chris Yates)

Image 2

Landspout (Photo by: Unknown)

Image 3

Waterspout (Photo By: Unknown)

Image 4

Dust Devil (Photo by: Unknown)


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