Dust Devil like circulation on shore of lake monona

At 215 pm a dust devil type circulation caused a pontoon boat that was on a hoist on a pier, on the east/southeast shore of Lake Monona to flip over. The boat owner was outside and witnessed the event.

Skies were clear, and low level lapse rates were steep (10.6 Celsius/km). Normally dust devils are seen with similar dry conditions and freshly plowed fields. In this case the circulation was not visible due to the lake and vegetation, and may have been aided by a slope in the terrain from the lake to the higher land overlooking the lake.

http://www.crh.noaa.gov/news/display_cmsstory.php?wfo=mkx&storyid=96648&source=0