photo #5488384

Most cloudspotters go a long time before catching their first horseshoe vortex cloud. A few like Talia Shilling Rabin (Member 51,247) are luckier. She saw this rare and fleeting formation over Lake Leelanau, Michigan, US shortly after joining the Cloud Appreciation Society. Talia knew what it was immediately, having read how rare it is in a Cloud-a-Day email. ‘When I saw this cloud,’ she said, ‘I freaked out.’ A horseshoe vortex forms in a region of horizontally rotating air – like a little gentle tornado turned on its side. This can develop when an invisible thermal of rising air encounters crosswinds overhead. Only when moisture conditions are just right will the cooling within this vortex cause droplets to appear as a twisting horizontal ribbon of cloud. This then curves into a horseshoe with the continued rise of the thermal. ‘The cloud moves very fast,’ Talia noted, ‘and then, before you know it, it’s gone.’