Dodge them if you can ! Even in little old Ireland, where we do not have extreme weather, I have experienced waterspouts - well, only once actually. Below is a report I wrote for a magazine in 1998.

"Down south the sailing started with the Blessington Spring Lamb event on 5th April. The first race started in a light force 2 and the cats drifted around for the first hour. A flash of lightning and a clap of thunder up at the north end of the lake woke everyone up. The wind started rising and black clouds moved in. Then a dark wall, of what turned out to be huge hailstones, swept across the lake towards the cats. The sound of the approaching hail on the water was amazing, but nothing to what came next. More thunder and Lightning and out in front of the wall approaching us came about four or five mini tornadoes. Not that mini, each one towered at least twice as high as our 30ft mast and had a large circle of churned up water at the base. They passed safely either side of the first Dart Hawk but Dermot McHugh and Julie McGuire on the second Hawk were not so lucky. They were hit full on as they were dropping their gennaker. The back of the cat was picked up in the air and swung around and the boat was thrown right over.
Dave and Susan Lynch's Dart 18 was also capsized. The "force eight plus" gale that accompanied all this only lasted about four or five minutes and within another ten minutes was down once again to a force two at the most."