What in the whirled? Romans are captivated as waterspout spins through the Tyrrhenian Sea off the coast of the Italian capital

 A massive waterspout has been caught on camera as it spun off the coast of Italy late on Thursday.  

The unusual weather phenomenon, which resembles a tornado, cut a swathe through the Tyrrhenian Sea, near the Roman town of Fiumicino, in Ostia. 

One image shows the whirling vortex with a boat visible in the far distance. 

Waterspouts develop over masses of water, scooping up vapour and dragging it towards the sky.

The slender 'tornados' are occasionally found in the late summer and autumn and can be dangerous for boaters and shoreline locations but are no threat farther inland since they collapse soon after they move onshore. 

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A massive waterspout has been caught on camera as it spun off the coast of Italy on Thursday. The unusual weather phenomenon (pictured), which resembles a tornado, cut a swathe through the Tyrrhenian Sea, near the Roman town of Fiumicino, in Ostia

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Waterspouts develop over masses of water, scooping up vapour and dragging it towards the sky. The slender 'tornados' are occasionally found in the late summer and autumn and can be dangerous for boaters and shoreline locations but are no threat farther inland since they collapse soon after they move onshore. (Above, the unusual weather event near Rome on Thursday)

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Waterspouts are whirling columns of air and water mist. They form when cumulus clouds grow rapidly. Above, a boat can be seen in the distance as the waterspout spins ferociously through the sea

However, the whirling columns of air and water mist can sometimes cause as much damage as a tornado.

They fall into two categories - fair weather waterspouts and tornadic waterspouts.

Tornadic waterspouts are associated with severe thunderstorms, and are often accompanied by high winds and seas, large hail, and frequent dangerous lightning.

Meanwhile, fair weather waterspouts usually form along the dark flat base of a line of developing clouds. By the time the funnel is visible, a fair weather waterspout is near maturity. 

A Fiumicino tromba d'aria in mare

Posted by Anacleto Rossano on Thursday, December 9, 2021

WATERSPOUTS: DEADLY FUNNELS THAT CAN RISE HUNDREDS OF FEET 

What are they and why do they form?

Waterspouts are whirling columns of air and water mist.

They form when cumulus clouds grow rapidly. These clouds are detached, fluffy-looking and cauliflower-shaped.

Cumulus clouds develop due to convection. This is when hot air rises and cools to form water vapour, which then condenses to form clouds. 

They fall into two categories: 'fair weather' and 'tornadic' 

(1) Tornadic waterspouts 

These are tornadoes that form over water, or move from land to water, and develop downwards during thunderstorms.

They have the same characteristics as a land tornado and can be accompanied by high winds and seas, large hail and lightning.

(2) Fair weather waterspouts 

These usually form along the dark flat base of a line of developing cumulus clouds and develop upwards from the surface of water.

They are generally not associated with thunderstorms and form in light wind conditions so don't move very much. 

The five stages of formation 

1. Dark spot: A light-coloured disk appears on the water's surface surrounded by a larger darker area

2. Spiral pattern: A combination of light and dark patches on the water spiral out from the dark spot

3. Spray ring: A ring of sea spray appears around the dark spot

4. Mature vortex: The waterspout reaches maximum intensity, making a funnel shape which appears hollow. It can rise several hundred feet.

5. Decay: The funnel and spray vortex begin to dissipate as the inflow of warm air into the vortex weakens

Sources: Met Office / National Ocean Service / National Weather Service