April 2, 2012
Weather Education Episode #5: How Are Waterspouts Different From Tornadoes?
RedOrbit Meteorologist Joshua Kelly
First, it is important to know that waterspouts occur over water only, and when they reach the coastline they quickly dissolve. But why? That question can be answered by looking more into detail of what makes up a water spout.
First, a waterspout comes from two types of clouds, the first being a towering cumulus cloud. The second cloud is the cumulus-nimbus cloud.
Next, a water spout is created by the upward motion of water being pulled from a large lake or ocean.
With that being said, if you take a waterspout and move it over land, you are removing its main source of energy -- the water. Also waterspouts are different from tornadoes in that their dynamic structure is very different.
For a tornado we learned that we need cold, dry and moist air all meeting together to get the atmosphere just right for a tornado to form. Also, for tornadoes we need a frontal boundary of some sort to move through the area.
While waterspouts don´t need the same conditions, all they need is to have the right amount of moisture in the atmosphere along with some type of wind curvature with height. Now, what happens is that with a waterspout, the formation usually occurs from the water´s surface upwards in those two types of clouds mentioned above. Then the waterspout will continue to spin over the open waters until the conditions become less favorable for it or it moves over land.
In the photo above we can see the water spout is actually beginning to die here. I was able to get this photo just as the waterspout was moving on shore. As it hit the land, the swirling of the system lasted for maybe 20 more seconds and then it quickly went back up in the cloud. In this image all that is left of it is the funnel cloud.
So how strong can waterspouts be? Waterspouts are usually weaker than a normal tornado and that has to do with a lot of the dynamics that tornadoes need to form. However, don´t be surprised as sometimes waterspouts can get strong and move things in the open seas around. The damage path with a waterspout is usually smaller than with a tornado, however.
What to do if you see a water spout? If you see a waterspout or the weather service says conditions are favorable for waterspouts to form, here are a few things you can do. First, if fishing or in a boat try to find the closest area of land to get to. If you are in the open waters then what you want to do is take your boat and drive sideways of the waterspout as most water spouts will continue to move straight. If you go at an angle to the waterspout this will allow you the fastest way to get clear of it. If you are on land the best thing you can do is back up away from the beach and just wait it out. As mentioned earlier most waterspouts will die out upon reaching the land anyway.