A horseshoe vortex is a short-lived wisp of cloud curved into a U or horseshoe shape. It forms when a rising thermal carrying a little cloud meets wind that changes with height — wind shear — which tilts and twists the rising air into a spinning, curved ribbon. Because air rises fastest at the warm core of the thermal, the middle bows ahead of the ends, bending the cloud into its horseshoe before it quickly evaporates.
Worth knowing
The horseshoe shape comes from differential rising speed — the warm core of a thermal lifts faster than its edges, so the cloud's middle outruns its ends and curls into the shape just before the whole thing dissolves, often within minutes.
Note
Still unsure it's the same cloud? Our app, Cloud Point— on iOS and Android — reads a photo and returns the likely type with altitude, useful when a formation is fading faster than you can look it up.
