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Weather Wise: Horseshoe Vortex

Horseshoe Vortex Cloud
Posted at 6:24 PM, Nov 22, 2021
and last updated 2021-11-22 20:24:53-05

HELENA — The horseshoe is a symbol of good luck and one of MTN’s viewers recently was very lucky to have witnessed and documented a horseshoe vortex cloud.

They form when there is a lot of vorticity (which is a measurement of rotation) in the air. Shallow cumulus clouds get the assist for the formation of horseshoe vortex clouds.

The vortex forms when the small cumulus updraft interacts with the surrounding air and forms a dipole vortex. The center of the forming cloud rises faster than the sides, forming a bow or horseshoe shape. The cloud is spinning or rolling like a dust devil or waterspout.

Horseshoe vortex clouds typically occur during the afternoon when the sun is heating the lower levels of the atmosphere allowing for upward motion of the air, creating spin.

Legend has it horseshoes facing downward are good luck.