Is a waterspout filled with water?

The start of the school year is often looked at as an unofficial sign that summer is coming to a close, but another unexpected signal was seen last weekend in Inverness County, N.S.: waterspouts.

Margy Krause says that despite having lived on a boat in the South Pacific for several years, this was her first waterspout sighting. Her caddie, who lives in Inverness County, says he’s seen many waterspouts.

It’s not surprising to see waterspouts at this time of year. Waterspouts can develop in dangerous storms or when cooler air passes over warm water. On Friday, a cold front swept down across the region after a stretch of very warm weather.

The two major types of waterspouts are tornadic and fairweather waterspouts.

Tornadic waterspouts are associated with a rotating updraft of a supercell thunderstorm. Influenced by winds associated with severe thunderstorms, air rises and rotates on a vertical axis. These are powerful and destructive.

Fair-weather waterspouts, however, are much more common and rarely dangerous. Fairweather waterspouts occur in coastal waters and are associated with dark, flat-bottomed, convective cumulus clouds.

Waterspouts of this type don’t often last much more than 20 minutes; average wind speeds are usually well below 100 km/h and they move along at 10 to 15 knots – less than 30 km/h.

Despite the name, a waterspout is not filled with water from the ocean or lake – a waterspout descends from a cumulus cloud; it doesn’t “spout” from the water. The water inside a waterspout comes from condensation inside the cloud.

Typically, fair-weather waterspouts dissipate when they make landfall and rarely penetrate far inland.

If you’re on the water, the best way to avoid a waterspout is to move at a 90-degree angle to its apparent movement.

While these types of waterspouts develop in less dangerous conditions, people should still take safety precautions: boaters should stay away from waterspouts and stick close to shore when a waterspout is spotted or when a waterspout watch is in effect.

Ominous skies over the Cabot Links Golf Course last Friday prompted Margy Krause to look up. That’s when she spotted this waterspout. If you look closely, you can see the spray vortex on the water.