Funny thing about waterspouts, you can have them with the normal, narly "gonna wind blast you" storm clouds. These occur in many parts of the world, see below. Then again, particularly in South Florida, perhaps further north in summer and especially the middle Keys, they can pop down in partially cloudy sunny weather from a not real threatening "appearing" cumulous clouds. I was thinking these are "fair weather waterspouts" and strangely enough that is was NWS calls them. More at: http://www.srh.noaa.gov/mfl/hazards/inf
I used to worry about them doing boat tow hang gliding down in Biscayne Bay of both varieties. I recall once having three in sight a couple of miles away during one tow years back. Also used to worry about them while free diving well offshore in summer. What are you going to do if one comes over and vacuums you up, out swim it?
Here's a bit about what NWS has to say about them:
Listen for special marine warnings about waterspout sightings that are broadcast on NOAA Weather Radio.
Watch the sky for certain types of clouds. In the summer, with light winds, look for a possible waterspout underneath a line of cumulus clouds with dark, flat bases. Anytime of the year, a thunderstorm or line of thunderstorms, can produce very intense waterspouts.
If a waterspout is sighted, immediately head at a 90 degree angle from the apparent motion of the waterspout.
Never try to navigate through a waterspout. Although waterspouts are usually weaker than tornadoes, they can still produce significant damage to you and your boat.
Lampu put this up from several years ago from Colonia, Uruguay. I would say these are not the fair weather variety of waterspouts. They have some intense weather down that way:
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Here is a good video clip of a waterspout in Miami brought in by some heavy weather.