Waterspouts are possible in Lake Michigan on Wednesday, including potentially in the Chicago area, forecasters warn.
The National Weather Service in Chicago postponed its weekly radio test Wednesday morning “due to the risk of thunderstorms and waterspouts in our Lake Michigan coverage area,” the agency said.
The test was rescheduled for Thursday between 11 a.m. and noon.
In the Milwaukee area, the National Weather Service warned residents to “be on the lookout for waterspouts,” with scattered showers and storms possible.
The footage showed what appeared to be a waterspout in Shorewood, Wisconsin, just outside of Milwaukee.
What is a waterspout?
According to the NWS, there are two types of waterspouts. They are called fair weather waterspouts and tornadic waterspouts.
“Tornadoes are tornadoes that form over water or move from land to water,” the NWS reports. “They have the same characteristics as a land tornado. They are associated with severe thunderstorms and are often accompanied by strong winds and seas, large hail and frequent dangerous lightning.”
Those seen in Lake Michigan appeared to be tornadic waterspouts.
“This is due to cold air above a uniformly warm Lake Michigan,” according to the NBC 5 Storm team, which warns that “direct contact can be dangerous.”
Fair-weather waterspouts develop on the water surface and accumulate upward, but are not usually associated with thunderstorms.
If a waterspout moves toward the coast, a tornado warning is issued, the NWS reports.