© David L. JohnstonA waterspout over Lake Michigan, seen from the Park Hyatt, 800 N. Michigan Ave.
More than a dozen waterspouts were spotted in Lake Michigan near Chicago Saturday morning, according to the National Weather Service.

The weather service received seven different reports between 6:30 and 11:15 a.m. about waterspouts, though some of them could have been the same waterspout viewed from a different position, said meteorologist Casey Sullivan.

There were waterspouts spotted over southern Lake Michigan from off Waukegan to Evanston to just north of Whiting Indiana, according to weather service.

Waterspouts are essentially tornadoes over water, Sullivan said.

"You definitely want to avoid them," Sullivan said. "If there's waterspouts, you want to head to port."

Fall is the "climatological peak" for waterspouts, as colder air coming over the warm water helps create instability, Sullivan said.

The threat of further waterspouts should end Saturday evening, and conditions have become "less favorable" for waterspouts as the day has gone on, Sullivan said.