Storm chaser spots rare ‘vortex cloud’ twisting over Mississippi. What caused it?
A rarely documented cloud that spins and folds itself all at once was photographed over Mississippi by a storm chaser.
Called a “horseshoe vortex cloud,” the strange formations are so infrequent and fleeting that photos are scarce, experts say.
Storm chaser Stan Dorroh saw the cloud forming around 4:40 p.m. on Feb. 21 in Starkville and seized the moment by stopping in the middle of a road. Starkville, home to Mississippi State University, is about 125 miles northeast of Jackson.
Dorroh managed to get a single photo, showing the strange cloud was ribbon thin, bent in the middle and rotating.
“I knew just how rare of a cloud formation it is. It was fairly large, but I have no way of putting any scale to it,” he told McClatchy News.
“The cloud dissipated probably less than a minute after I took the picture. It was gone before I could get it posted to Twitter. ... Glad now I decided to not wait until I was parked.”
His photo was shared on Facebook by the North Mississippi Storm Chasers & Spotters, where many commenters admitted they had never heard of such clouds. The group’s 73,000 followers share a “common interest and love of severe weather.”
“Horseshoe vortex clouds (are) one of the hardest clouds to find and one of the quickest to disappear,” the group wrote on Facebook.
“This has nothing to do with missiles, UFOs, and balloons.”
It’s mostly the result of warm and cool air colliding in just the right way, experts say.
The formations appear when a horizontal cloud drifts over a column of warmer air, the group explained. On occasion, the warmest part of the air column will hit the cloud dead center, causing that spot to rise fastest, creating a horseshoe shape.
“The different updraft speeds also give this cloud formation a bit of spin, which is why it is caused a vortex cloud,” the group said.
“As the cloud rises, it often finds stronger winds at higher elevations and, thus, the top (or middle) of the cloud spins faster and allows it to pull up and away faster.”
Conditions are rarely perfectly aligned, and even then, the “subtle little wisp of cloud” evaporates in a minute or two, according to the Cloud Appreciation Society. The scenario doesn’t include rain or severe weather of any kind, the society says.
Dorroh reports weather conditions were “nice” when he saw the cloud, with a partly cloudy sky and temperatures in the 70s.
He started storm chasing in 2012, saw his first tornado in 2013, and joined North Mississippi Storm Chasers & Spotters in 2015.
“This is the second (horseshoe vortex) I have seen. The first one was several years ago on an actual day I was storm chasing, but it was much smaller in size,” he said.
This story was originally published February 27, 2023 at 4:32 AM with the headline "Storm chaser spots rare ‘vortex cloud’ twisting over Mississippi. What caused it?."