October 29, 2012
As the eastern seaboard braces for Hurricane Sandy, a storm of possibly unprecedented power, I thought I’d take a look back and see what the strongest October storm ever was. I didn’t have to look far, as it’s actually the Great Lakes storm of late October 2010:
On October 26, 2010, the USA recorded its lowest pressure ever in a continental, non-hurricane system, though its pressure was consistent with a category three hurricane. The powerful system was dubbed the “Chiclone” by the media as it hit the Chicago area particularly strongly, as well as Minnesota, Wisconsin and Michigan. It was also meteorologically referred to as a bombogenesis due to the rapid drop of barometric pressure experienced.
…The storm also produced some of the highest officially recorded waves by weather buoys stationed in Lakes Superior and Michigan. Specifically, on Wednesday, October 27, 2010, buoy no. 45136, operated by Environment Canada, in northern Lake Superior recorded a significant wave height of 26.6 feet (this is average height of 1/3 of the highest waves over an hour), and buoy no. 45002, operated by the National Data Buoy Center (NDBC), recorded a significant wave height of 21.7 feet in northern Lake Michigan. The NDBC and many models indicate that multiplying significant wave height by a factor of approximately 1.3 will equal the approximate average height of the highest 1/10 of waves recorded -here that would translate into such average wave heights of approximately 34.5 feet and 28.2 feet on Lakes Superior and Michigan respectively [please verify]. This would appear consistent with the NOAA forecast for northern Lake Michigan calling for 21-26 foot waves that day. The persistence and strength of the storm’s westerly winds also piled the waters of Lake Michigan along the Michigan shoreline leading to declines in lake levels on the Illinois and Wisconsin side of the lake. Based on NOAA lake level sensors, an updated analysis of Wednesday, October 27, 2010 water levels on Lake Michigan revealed a two-day decrease of 42 inches at Green Bay, WI and 19 inches at Calumet Harbor, IL—while NOAA sensors at Ludington, MI and Mackinaw City, MI measured lake level rises of 7 and 19 inches respectively.
A 78 mph gust was recorded the afternoon of October 27, 2010 at the Harrison-Dever Crib, three miles offshore of Chicago in Lake Michigan.
You can read a detailed account of the damage in the October North American Storm Complex on Wikipedia and also read Dr. Jeff Masters’ analysis of the storm at Weather Underground.
More Michigan weather on Michigan in Pictures.