Cory Lutz via Storyful
Thunderstorms helped produce a massive waterspout off the coast of Destin, Fla., on Tuesday, wowing people who saw video of the cool-looking weather phenomenon.
If you’ve never seen a waterspout before, you might think it’s a tornado happening over water instead of land – and that’s pretty much what is going on.
How waterspouts form
To understand the conditions needed to form a waterspout, according to the National Weather Service, you’ve got to understand vorticity, or an area of localized spin.
For vorticity to occur, winds from opposing directions have to meet over a small area — or you have increasing winds come from any direction.
“For example, a wind out of the west at the coastline and a wind out of the east 5 miles offshore would form a pool of vorticity in the immediate vicinity of the coast,” the NWS Mobile location in Alabama said on Twitter.
There’s usually a boundary between the two winds, and the stronger the winds are, the stronger the vorticity is, NWS Mobile said.
Next up, you need a wind shift, where the wind will change directions in a short period of time.
Then you add the water. A shower or storm in the area means there will be an updraft that can continue to feed “warm, moist air into the storm to develop [or] maintain the cumulus or cumulonimbus cloud,” NWS Mobile said.
“This updraft can also act to pull any surface vorticity upwards if strong enough and located over a region of vorticity,” NWS Mobile said. “If the vorticity is sufficiently stretched and likewise tightened up, then a waterspout can be formed. Think about an ice skater lifting their arms as they spin, helping to speed up the rate at which they spin.”
The waterspout in Destin was stronger than normal
Conditions in Destin, including 10 to 20 mph winds and intense thunderstorms, contributed to the “spectacular results” that dazzled many.
“Typically they are not as extreme as this one, but even weaker storms can generate waterspouts if the basic ingredients are present,” NWS Mobile said.
And waterspouts don’t just form over oceans. They’re also known to form over lakes including the Great Lakes.