Matt Taylor
BBC Weather

Witnesses describe seeing a waterspout form during the storm before the Bayesian yacht sank.

Most of us are aware of what tornadoes are – rotating columns of destructive winds, protruding from the base of clouds down to the ground.

Waterspouts are just that too, but are over water rather than land. Instead of dust and debris swirling around the core of strong winds, it’s water mist whipped up from the surface.

Like tornadoes, most are only short-lived, narrow columns and are not easily picked out on weather radars, so many will go unreported.

However, they are not as rare as you may think. According to the International Centre for Waterspout Research, there were 18 confirmed waterspouts off the coast of Italy on 19 August (the day the yacht went down) alone.

In the northern hemisphere, waterspouts are most common in late summer and through the autumn, when sea temperatures are at their highest, fuelling the storm clouds. But with sea temperatures rising due to climate change, there is a concern that they could become more common.

In the last week, the Mediterranean has registered its highest sea surface temperature on record, which has helped to energise this recent storm outbreak.