Summer afternoons on the Gulf Coast follow a pattern: clear morning, towering clouds by early afternoon, then a storm that rolls through and clears out again before dinner. Most days that's the whole story. Every so often, though, one of those storms reaches down and touches the water, and for a few minutes there's a spinning column standing between you and the horizon. That's a waterspout, and it's a real, if occasional, part of a Gulf Coast summer.
What you're actually looking at
Most waterspouts near Florida are what meteorologists call "fair-weather" waterspouts. They form under a building cumulus cloud rather than a full-blown severe thunderstorm, and they tend to be weaker, slower-moving, and shorter-lived than a tornado. They usually drift with the wind rather than the wind rushing into them, which is part of why they can look almost lazy from a distance. Florida sees more of these than almost anywhere else in the country, mainly because the state's wet season, roughly June through September, produces exactly the warm, moist, unstable air they need, day after day.
There's a second, less common type worth knowing about: a waterspout spun up by an actual severe thunderstorm, which behaves much more like a true tornado and can carry real wind speeds. One of these came ashore in Tampa a few years back and tore through a harborside neighborhood with wind gusts strong enough to damage roofs and flip patio furniture before it lifted. That kind is rarer, but it's the reason waterspouts aren't purely a spectator sport.
Does this actually happen near Siesta Key?
Yes. The National Weather Service's Tampa Bay office has issued specific reports of waterspouts forming along a line running from near Sarasota Bay down toward Gasparilla Island and Bonita Beach during summer storm outbreaks. I haven't personally stood on the beach and watched one form off Siesta Key, so I won't pretend this is a daily occurrence you're guaranteed to catch — but the conditions that produce them are the same conditions that show up over this stretch of coast most summer afternoons, and NWS records confirm they've formed right along this part of the Gulf.
If you actually see one
From the sand, the safest move is the boring one: if a waterspout is visible anywhere near shore, treat it the same way you'd treat an approaching thunderstorm. Get off the beach, away from the water, and away from anything metal like an umbrella pole. Fair-weather waterspouts usually weaken quickly once they cross onto land, but "usually" isn't a guarantee, and the storm attached to it can still bring lightning regardless of what the funnel is doing.
If you're out on the water, the National Weather Service's guidance is to move away from it at a right angle to its path rather than trying to outrun it in a straight line, since that's the fastest way to get clear of its actual track. Small boats have no business being anywhere near one.
None of this is meant to make a fairly rare, mostly harmless phenomenon sound like a hurricane. Most people who spend years on this coast never happen to be looking at the right patch of water at the right moment. But if you are, it's a genuinely strange thing to watch unfold, and it helps to know what you're looking at instead of just standing there confused.