Horseshoe Vortices at Sunset, October 26


May 5, 2019
Owasso, OK
This past October 26, a dissipating "cloud street" broke up into 2-3 horseshoe vortices. Cloud streets were pretty prevalent during the day but were increasingly dissipating with time as the afternoon wore on.

A single remnant cloud street caught my eye on the way into town to run some errands: the last of its kind for the day. A short time later, on my way back home, I saw what looked like a "question mark" out of the corner of my eye, and pulled over as quickly as I could. You can tell I was taking iPhone pictures as I crept through a parking lot looking for a good view of the western sky.... Minutes count and in a scant 3 minutes the horseshoe vortices were gone.


I'm pretty certain the cloud streets that day were associated with horizontal convective rolls (HCR), which raises the question of how much the HCR contributed to the horseshoe vortex formation. I wish I had paid more attention to the sky earlier in the day--I probably missed a great show.
Nice catch! Those are nice pics! It's truly amazing to see those unexpectedly. I saw one in Oct. '22 in Virginia on a cloudless day, near sunset. They are more prevalent preceding severe weather events.