A luxury superyacht carrying 22 passengers, including British tech mogul Mike Lynch, tragically sank off the coast of Palermo, Italy, on August 19. The incident occurred in the early morning hours when the 183-foot yacht, named Bayesian, was reportedly struck by a waterspout—a tornado-like phenomenon that forms over water. The sinking of the Bayesian raises concerns about the potential increase in these powerful weather events due to climate change, especially in rapidly warming bodies of water like the Mediterranean.
Waterspouts: Nature’s Tornadoes Over Water
A waterspout is essentially a tornado that forms over a body of water. Unlike tornadoes on land, waterspouts can develop over any surface as long as the conditions are right. According to David Sills, executive director of the Northern Tornadoes Project at Western University in Canada, “The tornado doesn’t care whether it’s over water, land, or anything else. It will do its thing regardless.”
These rotating columns of air emerge where there’s an air boundary, such as the collision between warm and cold air masses. The Australian Government Bureau of Meteorology (BOM) explains that changes in wind direction at different altitudes can initiate this rotation. Meteorologist Peter Inness from the University of Reading adds that when winds at different heights blow in opposite directions, the air caught between these layers starts to spin horizontally. As warm air rises from the water’s surface, this spinning air gets lifted and stretched, concentrating near the water and creating a vortex—a waterspout.
As the air is drawn upward into the storm, the rotation intensifies, much like water spiraling down a bathtub drain. Inness compares this to a figure skater pulling in their arms to spin faster and faster.
The Dangers of Waterspouts for Maritime Vessels
While waterspouts are capable of generating winds up to 55 miles per hour, they usually move slowly—at less than 25 miles per hour—and are short-lived. Because of this, they often don’t cause significant damage. The BOM notes that waterspouts typically affect a single location for only a few minutes.
However, when it comes to maritime safety, the threat posed by waterspouts should not be underestimated. Although it has not been confirmed that a waterspout sank the Bayesian, the possibility remains. “It was dark, and no images are available,” notes Luca Mercalli, president of the Italian Meteorological Society.
Boats are generally built to withstand strong winds, with design features like a heavy keel that helps right the vessel if it’s tipped over. But when a boat takes on water, it loses buoyancy, a situation known as a “knockdown.” If a vessel is overturned for too long, waves can flood open hatches or doors, leading to a rapid loss of buoyancy and eventual sinking.
Additionally, rapid changes in wind strength and direction can cause boats to rock violently, further increasing the risk of capsizing, according to Inness.
Could Climate Change Be Driving an Increase in Waterspouts?
Research indicates a correlation between higher sea surface temperatures and an increased frequency of waterspouts, particularly in regions like Spain’s Balearic Islands. A study has shown that waterspouts are more likely when sea temperatures range between 73°F and 78°F. This year, the Mediterranean is experiencing temperatures over 5°F above average—a situation described by Mercalli as an “extreme anomaly.” Such unusually warm waters could be attributed to both climate change and natural variability.
Some experts warn that global warming may intensify weather events, including tornadoes on land and waterspouts at sea. “Global warming injects more energy into the atmosphere, which could amplify all extreme weather events,” says Mercalli. However, establishing a direct link between climate change and the frequency of waterspouts is challenging. The BOM cautions that waterspouts are brief and localized phenomena, making it difficult to attribute their occurrence directly to climate change.
As the Mediterranean warms more rapidly than other oceans, it’s uncertain how this will impact the formation of waterspouts. While warmer sea temperatures are a contributing factor, other conditions are also necessary for waterspouts to develop. For instance, a temperature difference between the air and sea is crucial. If both air and water are warming at the same rate, the likelihood of more waterspouts could decrease, suggests Sills.
Low atmospheric pressure is another essential condition. Even with exceptionally warm waters, high pressure over the Mediterranean would prevent the formation of thunderstorms—and by extension, waterspouts. Additionally, the direction of the wind plays a role; in the Mediterranean, humid air from the north is more likely to trigger storms than dry winds from North Africa.
Due to the lack of historical data, it’s difficult to confirm whether waterspouts are becoming more common. However, Mercalli points out that severe storms—including those that produce strong winds, heavy rain, and hail—are increasing globally, including in Italy.
