MEMPHIS, TN (WMC) -When at the beach, sometimes you will see a rotating column of air moving across the ocean. While it looks like a tornado we see on land, this cone of cloud-filled wind is called a Waterspout.
The technical term for a waterspout is a column of cloud-filled wind rotating over a body of water. While the name has water in the title, it is not technically filled with water.
A waterspout descends from a cumulus cloud over an ocean or lake, it does not rise upward from the water. The water inside a waterspout is formed by condensation in the cloud.
There are two different types of waterspouts: tornadic and fair-weather waterspouts.
Tornadic waterspouts gain their start like true tornadoes. Influenced by winds associated with severe thunderstorms, air will rise and rotate quickly on a vertical axis. This form of waterspout is the most powerful and destructive type.
Fair-weather waterspouts are much more common and are rarely dangerous. The type of cloud from which this form of waterspout is descended from are not fast moving, so they usually stay static. Fair-weather waterspouts are associated with developing storm systems, but not storms themselves.
For a waterspout to form, high levels of humidity and relatively warm water temperatures are needed compared to the overlying air. This means that waterspouts are more common in tropical and subtropical waters.
There are 5 stages to waterspouts:
1. Dark Spot – The surface of the water will take on a dark appearance where the vortex, or column of rotating wind will reach 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, like a hurricane.
4. Mature Vortex – The waterspout is now at its most intense stage, meaning it is visible from the surface of the body of water to the clouds over head. It gains its hollow funnel and could be surrounded by vapor.
5. Decay – This is when the flow of warm air into the vortex will weaken, the waterspout will dissipate.
Quick facts about a waterspout, it is around 165 feet around with speeds around 50 mph, which is close to an EF-0 tornado on land. Some of the largest can grow to 330 feet around and go for up to 1 hour. Usually these storms are on average 5 to 10 mph.
The National Weather Service does recognize the dangers and will post warnings on waterspouts as it could put swimmers, boaters and even aircrafts at risk.