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What is a landspout and how did one tear through a Colorado business park?

What caused this landspout tornado near Denver? The setup explained
What caused this landspout tornado near Denver? The setup explained 00:55

When we normally think of a tornado, most people go to Twister or picture the Wizard of Oz. They think of the powerful storms spinning down from massive, rotating thunderstorms, triggering tornado warnings, and potentially causing major damage.

However, not all tornadoes form the same way, and with recent storms across Colorado, we have seen those in the form of landspouts.

A landspout tornado is a less intense tornado. It looks like a skinny rope extending from a cloud to the ground. It can spin quickly and may even pick up dust or debris, but it's usually weaker and shorter-lived than the classic tornadoes we see in severe weather outbreaks.

What is a landspout and how do they form? 00:20

Landspouts typically form on hot, dry days when there's instability and thunderstorms overhead, but the landspouts lack the rotating core of a mesocyclone that drives more dangerous tornadoes.

Low pressure at the surface forms rising air that rushes in, filling the low and increasing the circulation, and rising. As a thunderstorm develops overhead, the updraft stretches the landspout up to the cloud. That stretching will tighten the rotation and create the landspout tornado.

The storm picks up dust and debris, much like a tornado. Eventually, the landspout picks up cooler air, which kills the circulation.

Landspout forms in Franktown, Colorado 00:25

The Franktown landspout on Monday caused damage and came to the area without much warning, as many landspouts do.

While the classic tornado forms from mesocyclones, and strong rotations that are easy to detect on radar, landspouts form from non-rotating, ordinary thunderstorms, usually along an outflow or dryline.

They happen quickly, near the surface, and don't often present warning signatures on radar.

Even though a landspout is usually weaker, it is still considered a tornado and should still be treated as such if you see a funnel forming in your area. 

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