On 19 August, the British-flagged luxury yacht Bayesian sank off the coast of Sicily during freak weather. Fifteen of the 22 people who were on board were rescued from the boat.
- Experts suggest the storm could have been a waterspout — essentially a tornado over water.
What is a waterspout?
- A waterspout is a whirling column of air and water mist. Despite its name, a waterspout is not filled with water from the ocean or lake.
- A waterspout descends from a cumulus cloud. It does not “spout” from the water. The water inside a waterspout is formed by condensation in the cloud.
Two types of Waterspouts
- Waterspouts fall into two categories: fair weather waterspouts and tornadic waterspouts.
- Tornadic waterspouts are tornadoes that form over water, or move from land to water. They have the same characteristics as a land tornado. They are associated with severe thunderstorms, and are often accompanied by high winds and seas, large hail, and frequent dangerous lightning.
- Fair weather waterspouts: Fair weather waterspouts usually form along the dark flat base of a line of developing cumulus clouds. This type of waterspout is generally not associated with thunderstorms.
Differences between Tornadic and Fair weather waterspouts
- While tornadic waterspouts develop downward in a thunderstorm, a fair weather waterspout develops on the surface of the water and works its way upward. By the time the funnel is visible, a fair weather waterspout is near maturity.
- Fair weather waterspouts form in light wind conditions so they normally move very little.
