This Colorado supercell thunderstorm features an unusual twist. Notice the sawtooth-like protrusions along the outer cloud wall. These are Kelvin-Helmholtz waves, like these fair-weather clouds we’ve seen before, but instead of occurring vertically, they project horizontally! That implies that the invisible layer of air just outside the cloud wall is moving faster than the wall itself. That creates shear along the outer edge of the cloud wall and causes these waves to form. This is the first time I’ve ever seen this sort of thing. What an awesome photo! (Image credit: M. Charnick; submitted by jpshoer)
Waves on a Supercell
