Sep 24, 2011 Waterspouts Over Lake Michigan (updated 130 pm 9/26)

(message for people who observed and/or took pictures of the waterspouts is found at end of this story)


Waterspouts Formed East of Milwaukee on Saturday Sep 24, 2011

A somewhat rare and fascinating weather pattern took shape over Lake Michigan on September 24, 2011.   Two important ingredients came together during the late morning and afternoon to produce a rare "outbreak" of waterspouts stretching from off shore of Milwaukee, south to the Chicagoland area.  The environmental ingredients responsible for this setup were simple; a seasonably cold airmass moving over Lake Michigan, at a time when the Lake Michigan water temperatures were still hovering in the lower to mid 60s.   This created a temperature difference of nearly 14 degrees Celsius, or about 25 degrees Fahrenheit, between the air at the water surface and the air at around 4000 feet (we call this the Delta-T.)  Amazingly, the showers and isolated thunderstorms that developed eventually had cloud tops that reached nearly 26000ft. This was due to the added heat from the warm lake temperatures.  



As the heat rose into the colder air aloft (simple convection), these convective updrafts lifted horizontally rotating boundaries of air that were hovering over the lake. These boundaries are subtle and undetectable without a dense observation network (a network that clearly doesn't exist over the lake.)  When these rotating boundaries are lifted vertically by the convective updrafts, they stretch and begin to rotate very quickly, and in some cases a waterspout forms.  Today was one of those days when numerous waterspouts formed.  See the impressive images below.

The following description of the development of two funnels was submitted to us by Karla Buck, who observed the event from the Milwaukee Art Museum grounds.

"One funnel was observed (rotation) at 10:35, making water surface contact at 10:36.  At 10:38 another funnel was observed (rotation) to the left/northwest of the waterspout.  The second funnel did not make surface contact and dissipated at 10:40.  The waterspout changed configuration, from only under cloud funnel and water surface contact evidence (shaft not visible), to obvious shaft to rope, dissipating at 10:45."




From Curtis Gibeaut

From Curtis Gibeaut

From Curtis Gibeaut

From Curtis Gibeaut

From James Heil

From James Heil

From Eric Johnson

From Steven Skalecki

From Karla Buck

From "Ed from the East Side"

From Willian Welburn

From Willian Welburn

From Willian Welburn

From Willian Welburn

If you have some waterspout photos you'd like to share with us, please ship us an email at

Check out a great waterspout write-up from the National Weather Service Office Chicago.





...Message to people who observed and/or took pictures of the waterspouts on Sep 24th...

What needs to be done:

1. Determine how may waterspouts occurred over Lake Michigan waters from the Sheboygan/Manitowoc border south to the Wisconsin-Illinois border during the late Saturday morning hours on Sep 24th.

2. Determine the exact beginning and ending times (to the nearest minute) and location-path of each waterspout.

3.  Determine if there were waterspouts at other times over the weekend.

Background information:

A waterspout is defined as "a violently rotating column of air extending from the cloud base to the water surface.  The visible condensation funnel may or may not extend all the way downn to the water surface.  Confirmation that the rotating column of air is in contact with the water surface is a visible, rotating, water-spray on the surface of the water.

How you can help:

Plot the position-path of waterspouts on a basemap of the Lake Michigan nearshore waters, and annotate the time(s) associated with the plotted locations-path.  E-mail your report and base-map to:  Refer to the base-map plot of the Lake Monona tornado/waterspout on August 8, 2011 by clicking here.

What we do know:

1.   Minimally 3 or 4 waterspouts east of the city of Milwuakee.

2.   A waterspout east of the city of Kenosha.

3.    Probably a waterspout east of the city of Sheboygan.

4.    Funnel cloud reports east of Mequon, but don't know if there were waterspouts.

5.    The watespouts occurred rougly between 10 A.M and 11 A.M. on Saturday Sep 24th.    


Return to Latest News is the U.S. government's official web portal to all federal, state and local government web resources and services.