This is the terrifying moment a swirling giant waterspout tornado formed off the coast of southern Thailand.

Dark grey clouds gathered around a mile from the shore in Trat province on Sunday morning (April 11) as winds suddenly picked up.

Locals watched in amazement as the elephant trunk-shaped tornado formed, stretching down from the gloomy clouds above into the sea below.

Footage shows how the tornado sucked up seawater into the vortex as the mass of storm clouds also began spinning.

Resident Awirut said: ‘I was scared when I saw the tornado. I thought it would come towards the beach and damage lots of homes. It was so big, it reminded me of an American movie.

‘It was the biggest tornado I’ve ever seen in the area. We have a lot of rainstorms, but nothing as big as this. Some people were running away they were so worried.’

Waterspouts are tornadoes that form over water. They are intense columns of swirling clouds that stretch from the surface to the clouds above.

They are most commonly found in subtropical areas and disappear shortly after they come into contact with land.

Waterspouts are generally not dangerous but they can be a risk for aircraft flying through the area and for coral reefs and marine life in the water immediately below.

Sailors should also try to avoid waterspouts – as the consequences of floating into one could be disastrous.

The most common type of waterspout is a ‘fair weather waterspout’. They happen when winds merge from opposite directions near the water’s surface, creating a small area of spin.

Sudden warm air at the surface, usually from a thunderstorm, causes the spinning air to rotate faster and it starts to rise – picking up water at the same time.

Sometimes the air spins so fast that it stretches and a funnel appears from the water to the thunderstorm cloud above.