Thursday, March 06, 2014

Winter of 2013/2014-- ice coverage of Great Lakes nearing a record

Coverage of the Great Lakes on Feb 13, 2014. Paler shades
represent greater ice coverage. Source: NOAA
The Great Lakes system is more than 90% covered by ice right now, and is approaching the record of 95% set back in 1994. The ice is forming very rapidly now-- for example, Lake Superior was 78% covered in the last week of February, and is now at 95% coverage. The maximum ice cover of the lower lakes typically forms by the end of February, and the more northerly lakes max out a little bit later.
The ice cover on the lakes affects weather patterns over a large area, particularly to the east. Open water contributes to lake effect snow, and pulls the jet stream northward . The  winter severity of the lake system itself  is sensitive to worldwide atmospheric circulation events such as el Nino or la Nina.

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