Chicago Storm: 85-MPH Derecho and Seiche

Jul 11, 2011; 6:09 PM ET

Chicago got a heck of a storm this morning when a derecho moved over the city, causing winds to gust to 75 mph at the Midway airport and a seiche on Lake Erie. Over 800,000 lost power in Chicago, the biggest outage ever.

Although not shown on the Michigan City, Indiana C-MAN Station Page, a look at the text data reveals a 38 m/s (85 mph) gust!

The NWS issued a Seiche Warning and in fact the city did see a drop (and rise) in the water level from Calumet – the level fell 28.15 inches in 24 minutes, including a fall of 22.37 inches in 12 minutes!

The NWS in Chicago has already launched a report on the storm, with damage lists and radar images. Over 280 reports of high winds were recorded by spotters: