Posted by: mrpeatie | June 8, 2009

What Exactly Are Waterspouts?

Up close with a waterspout near Florida

Up close with a waterspout near Florida

The two waterspouts that formed in the Charleston area over the last couple of days were part of storms that did not have tornado warnings associated with them, so how can they be considered tornadoes and what exactly is a waterspout then? The easy answer is that a waterspout is a tornado that just happens to form over water, but that isn’t completely correct.

Regular tornadoes are associated with the rotating updraft of a supercell thunderstorm that form from the subduction/adduction interaction between colliding fronts. The Charleston waterspouts, and the storms they were associated with, were non-tornadic (hence the lack of tornado warnings) and were formed from different, less violent, atmospheric conditions than conventional tornadoes. These kind of waterspouts generally rate no higher than an EFO on the Enhanced Fujita scale and generally have winds less than 67 mph. You can have much stronger waterspouts with winds speeds well above hurricane strength as well as tornadic waterspouts, which are tornadoes formed from supercell thunderstorms that are over water.


If you watch the Weather Channel at all, you’ve probably seen them talk about the Vortex2 tornado study which is a 7-week study using over 100 storm chasing vehicles. The team had been largely frustrated over most of the study due to a quiet tornado season, but they caught an epic twister in Goshen County, Wyoming late last week. The video is pretty amazing which includes a few moments where the tornado actually turns slightly horizontal and you can see into it.



  1. I always learn so much from you. Waterspout, tornado, they all freak me out!

  2. […] Charleston Waterspouts Two waterspouts were spotted earlier this week in the Charleston area. The first one was off Edisto beach on Thursday and the second one was spotted over the Cooper River near the Ravenel Bridge yesterday. Pics are from Live5News and their Twitter feed. They also posted some video of the Ravenel Bridge waterspout. And if you were wondering why there were no tornado warnings for these storms, it’s because waterspouts aren’t really tornadoes…sort of. […]

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