What is a waterspout?

Video caption, Amazing pictures of huge waterspout. (Footage from Le Temps d'une pose).

A huge waterspout has appeared off the coast of Bastia, a city on the French island of Corsica.

The scale of the phenomenon can be seen as it formed next to a huge cruise ship in the city's harbour.

What is a waterspout?

A waterspout is a whirling column of air and mist that can form over oceans, seas or large lakes.

They can be just as dangerous as a tornado if you get close to one in a boat.

Image source, PIERRE MATTEI

There are two types of waterspouts - a fair weather waterspout and a tornadic waterspout.

Tornadic waterspouts develop downward during a thunderstorm and can be accompanied by high winds and lightning, whereas a fair weather waterspout develops on the surface of the water and works its way upward.

As the name suggests, a fairweather waterspout forms in light wind conditions and usually doesn't move very far or fast.

It may look like it is sucking up water, but a waterspout's main visible cloud is formed by condensation of water vapour.