Contribution of Lake-effect to Annual Snowfall Totals in the Vicinity of Lakes Michigan, Erie, and Ontario

In the Great Lakes region, total winter snowfall receives contributions from both lake-effect (LE) and non-LE events. This research examined these separate contributions with a focus on the winters (October-March) of 2009/2010, a less active winter in terms of LE cloud cover, and 2012/2013, a more active LE winter, for the regions surrounding Lakes Michigan, Erie, and Ontario. Based on the presence and characteristics of cloud cover observed using GOES visible satellite imagery, each day was classified into one of two categories:  days with LE present over the specified lake or days with no LE over the specified lake. GIS analyses using SNOw Data Assimilation System (SNODAS) snowfall data from the two winters were used to examine the snowfall contribution from LE and non-LE days. 

In general, LE days exhibited a maximum of snowfall contribution in the typically defined snowbelts of each region while non-LE days tended to provide a more even distribution of snowfall throughout the regions in the vicinity of Lakes Michigan, Erie, and Ontario. The percent contribution for LE days to the annual snowfall varied by region, ranging from 20% to over 60% with dependence on location and winter. Results also indicated that although LE snowfall amounts tended to be greater during the more active LE winter, the percent of LE contribution to the annual snowfall totals was not necessarily dependent on the LE activity. The LE snowfall contribution to annual winter totals was found to be larger in the more active LE winter for Lake Ontario, smaller in the more active LE winter for Lake Michigan, and nearly equal in both winters for Lake Erie.