What caused the sinking on Monday of a sailing yacht carrying the British billionaire Mike Lynch and 21 other people off the coast of Sicily is still unknown. But some attention has focused on observations by witnesses, who described seeing a small tornado-like column known as a waterspout forming over the water during an abrupt and violent storm as the vessel sank.
Fifteen passengers on the 180-foot yacht, the Bayesian, escaped on a raft before being rescued by a neighboring cruise ship. The body of the ship’s cook was recovered on Monday and six people remain unaccounted for, including Mr. Lynch and his daughter Hannah, according to officials with Sicily’s civil protection agency.
Prosecutors in the nearby city of Termini Imerese have opened an inquiry into the cause of the sinking.
Here is what to know about waterspouts, a surprisingly common weather phenomenon that may have helped sink the luxury yacht.
What are waterspouts?
Waterspouts are columns of spinning air and moisture — similar to tornadoes over water, according to the National Weather Service.
While some form in fair weather, and are aptly called fair weather waterspouts, another more dangerous variety called tornadic waterspouts develops downward from a thunderstorm. These tornadic waterspouts can either form as regular tornadoes over land and move out to sea, or form in a storm already over a large body of water, according to the National Oceanic and Atmospheric Association.
Fair weather waterspouts are weak, often dissipate quickly and do not cause major damage, according to the agencies, but tornadic waterspouts are more often associated with high winds, dangerous and frequent lightning, and hail. The Italian authorities recorded strong winds and intense lightning activity at the time the yacht went down.
How common are waterspouts?
Experts say waterspouts may be more common than tornadoes, but because oceans are so vast, they are more difficult to track — and as difficult to predict.
“The Mediterranean is possibly one of the places where waterspouts are most likely around the world due to the warm ocean surface and a climate that is very susceptible to thunderstorms throughout the summer and autumn,” according to a statement by Peter Inness, a meteorologist at the University of Reading in the United Kingdom.
Mr. Inness pointed to a 2022 study by scientists from University of Barcelona, which found that waterspouts occurred more frequently over warmer sea surfaces. The North Atlantic ocean has been unusually hot for over a year, repeatedly reaching record highs for the time of year, according to data from the oceanic association.
The International Centre for Waterspout Research on Monday said on X, the platform formerly known as Twitter, that it had confirmed 18 waterspouts near Italy in recent days, and several fishermen in the area of the accident told Italian media that they had witnessed a waterspout near the yacht.
What may have happened?
Karsten Börner, the captain of the nearby boat that rescued the 15 passengers, said in an interview that he saw the Bayesian about 490 feet away before the wind and lightning picked up.
While it was difficult to see what happened amid the storm, “my theory was that she was capsized first and then went down over the stern,” he said.
Towering over 237 feet tall, the Bayesian mast was one of the tallest aluminum masts in the world and it also had a special keel that could be raised or lowered, according to its manufacturer, Perini Navi. A keel is the downward-extending centerline underneath a boat that can help stabilize the vessel.
“In this case, having a tall aluminum mast would not make it the safest port to be in case of a storm,” said Andrea Ratti, associate professor of nautical design and architecture technology the Politecnico di Milano.
He added that “a lot of questions will remain until we have other elements at our disposal.”
Elisabetta Provoledo contributed reporting.
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