Vortex spins up in roll cloud near Claremont, Minnesota

A man named Nick Dewhirst captured a cool horizontal vortex near Claremont, Minnesota, during mid-afternoon on May 19. The vortex spun up in a roll cloud generated by rain-cooled air from a thunderstorm. The man said explained the phenomenon of the vortex by saying: "collision of this cool airmass with a warmer one ahead of it, leads to vorticity in the vicinity, causing this motion".