Waterspouts

A waterspout is a column of wind, that can become cloud-filled, rotating over a body of water. This phenomenon is uncommon across coastal waters of Trinidad and Tobago.

How Do Waterspouts Form?

Despite its name, a waterspout is not filled with water from the ocean or lake. A waterspout descends from a cumulus cloud. It does not “spout” from the water. The water inside a waterspout is formed by condensation in the cloud.

There are two types of waterspouts, fair-weather waterspouts, and tornadic waterspouts, which get their start as true tornadoes.

Tornadic Waterspouts

Influenced by winds associated with severe thunderstorms, air rises and rotates on a vertical axis. Tornadic waterspouts are the most powerful and destructive type of waterspout only if it moves near mariners or onshore.

“Fair-weather” Waterspouts

Fair-weather waterspouts, occurring in coastal waters and are associated with dark, flat-bottomed, developing convective cumulus towers, like today’s waterspout. Waterspouts of this type rapidly develop and dissipate, having life cycles shorter than 20 minutes. They usually rate no higher than EF0 on the Enhanced Fujita scale, generally exhibiting winds of less than 108 KM/H.

The Formation of a Waterspout
The Formation of a Waterspout

Both tornadic and fair-weather waterspouts require high levels of humidity and a relatively warm water temperature compared to the overlying air. Waterspouts are most common in tropical waters like the Caribbean and the Florida Keys, and in subtropical waters, such as the islands of Greece, and off the east coast of Australia.

There are five stages of waterspout formation:

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

The average spout is around 50 meters (165 feet) in diameter, with wind speeds of 80 kilometers per hour (50 miles per hour), corresponding to the weakest types of tornadoes on land. The largest waterspouts can have diameters of 100 meters (330 feet) and last for up to one hour, though the average lifetime is just 5 to 10 minutes.

Facebook Comments