MILWAUKEE COUNTY, Wis. (WFRV) — Waterspouts were observed Wednesday morning in the southern portion of Lake Michigan, according to Special Marine Warnings issued by the National Weather Service Office in Milwaukee. But what exactly is a waterspout, and when do they occur the most?

A waterspout tornado is simply a tornado that forms over water or forms over land and moves over a water mass, like a bay, large lake or ocean. These tornadoes carry the same characteristics as land-based tornadoes, with a cloud base and funnel cloud.

These waterspouts occur the most during the month of September, according to the Mariners Weather Log, published in 2004 by the National Oceanic Atmospheric Administration. The post says in a calendar year, nearly 40% of waterspouts over the Great Lakes occur in the month of September.

Video provided to Local 5 Wednesday morning by Ron in Cudahy shows a waterspout tornado moving across the lake, with a great view of the condensation funnel and the cloud base above.

Another Video provided to Local 5 from AJ in Milwaukee on top of the Northwest Mutual Tower shows another view of a waterspout tornado from a distance.

These tornadoes can be very impactful to mariners, as they can overturn and damage boats and ships in their path.

What is the best way to stay safe while out on the water? Always listen to your NOAA Radio for Special Marine Warnings, and keep your eyes on the sky.

If one is spotted, travel 90 degrees from its motion and never travel through one, according to a post from the National Weather Service in Miami, Florida.