A waterspout is not a tornado that forms over water (as a lot of people think). It only becomes a tornado if it moves over land. If a tornado moves over water than it is a waterspout. Unlike tornadoes though, they can form from almost any kind of storm. Waterspouts may range from a small thunderhead to a massive hurricane. A tornado takes a lot more to form than a waterspout (i.e cool dry air has to meet warm moist air to create a storm that could be capable of producing a tornado). Waterspouts tend to be smaller than a tornado. That does NOT mean they are weaker (contrary to popular belief). Waterspouts have been known to sink ships and rip the roofs off of beach side condos when they spin onto land! People have reported that waterspouts make a hissing and/or sucking noise. Waterspouts actually do not suck up the water they're over, because the water is too heavy and has a lot more mass. Any water they can suck up, is extremely little and does not make it a fact that they are partially made of water.
What have waterspouts been known to do?
Waterspouts have been known to have a lot of personality. People have told stories of waterspouts raining strange things on land, such as fish and frogs. Another thing they have been known to do is frighten sailors. Waterspouts are extremely dangerous to boats. The last thing a boat pilot would want to do is get caught near one of these wild, windy whirlwinds. Waterspouts have killed many people on boats, from throwing people off, to sinking big ships entirely! They are underestimated on land. Although, they shouldn't be!
Should we take them seriously?
Waterspouts are definitely something to be cautious with. There are many people who think it's "safe" on land when they see one. But the fact is, you don't want to be anywhere near a waterspout as they can travel up to 70 miles per hour. Treat them as a possible threat! Unfortunately, there are a number of people who don't take them into consideration, regardless of wherever they are. Many people should be aware of the considerable danger they COULD be put in. (They aren't always going to come near land or come close to boats, but you should still be very weary of them). If you are put in a situation of being caught up near a spout, try to hide in a low area.
How common are waterspouts?
Common sites depend on where you are. If you are in a place that is surrounded by, or close to water during storms, then you will more inclined to see one. Places such as the Florida Keys get them all the time (or just Florida in general. [I know from experience]. Grand Isle in Louisiana has had some very destructive waterspouts (check out video in "Videos" page), and Australia has had some of the biggest and most destructive (check out that link in the "Videos" page). In a nutshell you'll hear about, and maybe even see a lot of waterspouts near a large body of water.
Does water temperature affect a waterspout's strength?
Water temperature actually does affect a waterspout's strength. Studies show that colder water makes a stronger, but smaller waterspout. Warmer water makes a bigger, but weaker one. The easiest way to show this is by making a dry ice tornado chamber. Just make sure the chamber has a dish in the middle of it to hold water and dry ice. This also explains the Grand Isle and Australia incidents. The Grand Isle waterspouts were not as strong as the Australia waterspout. This is because Australia has colder water than Grand Isle LA.