Spectacular slender-like tornado spotted off the coast of North Avoca

A man has captured footage of a waterspout off North Avoca, but did you know that these weird weather phenomena are not acutally filled with water at all? It’s way stranger than that.

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A Central Coast man has captured a spectacular water spout off the coast at North Avoca.

The footage was taken by David Craig on Wednesday with the long thin spout remaining fairly static off the coastline.

The phenomenon closely matches the Australian Bureau of Meteorology’s (BOM) description of a typical water spout.

“A waterspout looks like a slender tornado, but occurs over water,” a BOM spokesman said.

“They are occasionally seen near the coast in the late summer and autumn when cool, unstable air passes over warmer waters.

Waterspouts at Terrigal on the NSW Central Coast, on a wet and windy day in 2011. Picture: Gosford City Council ranger Paul Curry

“Nearby topography and other effects, allows local concentration (or convergence) of the airflow, which results in vigorous updraughts “tightening up” into spinning columns.”

According to the National Geographic Encyclopia, the term waterspout was a misnaming because the spout is acutally a “column of cloud-filled wind rotating over a body of water”.

The waterspout is not filled with water at all, but instead descends from a cumulus cloud.

“It does not ‘spout’ from the water. The water inside a waterspout is formed by condensation in the cloud,” a National Geographic spokesman said.

There are two major types of waterspouts: tornadic waterspouts and fairweather waterspouts.

The first are more similar to true tornadoes, influenced by a combination of winds and severe thunderstorms. These can be very destructive.

A caravan picked up by a waterspoutat at the Dunleith Camping and Caravan Park, The Entrance North, in 2009.

An example of this kind of water spout hit Dunleith Tourist Park at The Entrance on May 2, 2009, when it picked up a caravan and dumped it into Tuggerah Lake.

Three women in the caravan were injured, including one with a broken arm.

Fair-weather waterspouts, on the other hand, are much more common. They are rarely dangerous.

The clouds from which they descend are not fast-moving, so fairweather waterspouts are often static.

Fair-weather waterspouts are associated with developing storm systems, but not storms themselves.

The Dunleith Tourist Park at North Entrance. Picture: Peter Clark

Both tornadic and fairweather waterspouts require high levels of humidity and a relatively warm water temperature compared to the overlying air.

Waterspouts are most common off the east coast of Australia.

How they form

1. Dark spot. The surface of the water takes on a dark appearance where the vortex, or column of rotating wind, reaches it.

2. Spiral pattern. Light and dark bands spiral out from the dark spot.

3. Spray ring. A swirling ring of sea spray called a cascade forms around the dark spot. It appears to have an eye at the center, similar to that seen in a hurricane.

4. Mature vortex. The waterspout is now at its most intense stage, visible from the surface of the water to the clouds overhead. It appears to have a hollow funnel and may be surrounded by vapour.

5. Decay. When the flow of warm air into the vortex weakens, the waterspout collapses.