A waterspout is a whirling column of air and water mist — and some are as dangerous as tornadoes. They come in two kinds, which form in very different ways.
A waterspout. According to NOAA's National Weather Service, the best way to avoid one is to move at a 90-degree angle to its apparent movement — never closer to investigate. Credit: NOAA.
Two kinds of waterspout
| Tornadic waterspouts | Fair weather waterspouts | |
|---|---|---|
| What they are | tornadoes that form over water, or move from land onto water | whirlwinds that form along the dark, flat base of a line of developing cumulus clouds |
| Storms | come with severe thunderstorms, often with high winds and seas, large hail and frequent dangerous lightning | generally not associated with thunderstorms |
| How they grow | develop downward from a thunderstorm | develop on the surface of the water and work upward; by the time the funnel is visible, it is nearly mature |
| Behavior | the same characteristics as a land tornado | form in light winds, so they usually move very little |
When one comes ashore
If a waterspout moves onshore, the National Weather Service issues a tornado warning, because some can cause significant damage and injure people. Fair weather waterspouts, though, usually break up quickly when they reach land and rarely travel far inland.
Sources
Based on "What is a waterspout?" from NOAA's National Ocean Service, a work of the United States government in the public domain.
许可协议： CC0 1.0（公有领域） · 改编自 oceanservice.noaa.gov
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