Lake-to-Lake Connection Influence on Lake-effect Snowfall Totals

Lake-effect (LE) snowstorms are widely studied events that produce substantial snowfall on the downwind shores of the Great Lakes. These storms may take many forms; one type, lake-to-lake (L2L) events, occur when a LE cloud/snow band develops over an upstream lake (e.g., Lake Huron), extends across an intervening land mass, and continues over a downstream lake (e.g., Lake Ontario). Experienced forecasters have suggested that LE snowfall would be enhanced in the vicinity of the downwind lake when a L2L connection is established; however this has not been examined quantitatively.  

LE snowfall events over Lake Ontario were examined for the winters of 2003/2004 through 2013/2014 using the SNOw Data Assimilation System (SNODAS) data provided by the National Weather Service’s National Operation Hydrologic Remote Sensing Center. GIS analyses of SNODAS data from the 11-winter period were used to compare (a) Lake Ontario LE days that had a L2L connection with Lake Huron and (b) Lake Ontario LE days that did not have a L2L connection (single-lake LE). On average, L2L events produced much higher snowfall totals than single-lake LE events, in some regions producing nearly 200-300% more precipitation. However, the average contribution of L2L events to annual accumulated LE snowfall in the vicinity of Lake Ontario was small because of their relatively infrequent occurrence during LE situations.