top of page

Tornado Formation

tornado_cameron.jpg

Listen to the vignette aired on KTXT

Tornado formation - Wild West Texas Weather
00:00 / 00:00

Tornado picking up a lot of dust (photo courtesyof C. Nixon).

Tornado Formation

 

It’s springtime afternoon in West Texas. The skies grow dark and ominous as angry, turbulent clouds loom overhead. The heavens have an eerie greenish glow as a strange prophetic calm settles over the area. Suddenly, the tornado sirens ring out and echo over the plains as you see an ever so subtle lowering of the clouds over the horizon. The minutes are tense as they pass, but, luckily, the skies begin to clear and the storm moves off to the east. West Texas is yet again safe from the threat of a tornado.

Tornado season in the Southern Plains is always eventful. In fact, an average of more than 1000 tornadoes are reported across the United States every year. Tornadoes can form in several different types of thunderstorms, but a majority of them are produced from a storm called a supercell. Supercells are large, isolated thunderstorms that are characterized by a spinning updraft. These types of storms are common in the Southern Plains, especially in the springtime. Interestingly, although most tornadoes are formed in supercells, only about 11% of supercells actually produce tornadoes! But why is that?

Meteorologists are still trying to figure out the exact answer to that question. One significant flow property used in tornado research is vorticity, a measure of spin in the air. Tornadoes are violently rotating columns of air, but they don’t just start spinning out of nowhere. That rotation, or vorticity, must originate from somewhere else and brought inward toward the storm.

One way to get rotation in the air is in the presence of vertical wind shear, or when the winds change with height. Another source of spin comes from the storm itself – sinking air within a thunderstorm can cause pockets of rotation. Imagine pouring milk into a bowl of water. When the milk hits the water, billows form where the milk and the water meet. Much like the billows in the bowl of water, similar billows form around sinking air in a storm. The billows contain vorticity and are believed to help form a tornado.

Strong thunderstorms have the ability to lift air upward quickly. If air containing enough spin is lifted upward, a tornado will form in that storm, because air is coming together below rising air.  Just as an ice skater spins faster when she pulls her arms inward, a tornado will form if the spinning air is concentrated enough. 

Tornadoes are incredibly dangerous but incredibly fascinating phenomena. West Texas gets its fair share of supercells and tornadoes, so this spring, when the weather turns wild, be sure to keep your eyes to the sky.

bottom of page