Ice Storm ’98 in Southcentral Canada and Northeastern United States: A Climatological Perspective

Dubbed Ice Storm ’98, an extreme weather event characterized by two synoptic systems in succession dropped about 70–100 mm (in terms of water equivalent) of freezing precipitation over southeastern Ontario, southwestern Quebec and northeastern New York during a 6-day period from January 5 to 10 in 1998. Individually, the two synoptic systems were not dramatically more extreme in freezing precipitation than other major freezing rain events (4 since 1961) which occurred in the past over the affected area. Some regions in the target area, however, were impacted more by the second system. Based on an analysis of the 500 hPa vorticity field during the ’98 event, we suggest that the 1997/98 El Niño had a role in creating a flow environment conducive to the rapid formation of the second synoptic system. In contrast, other major freezing rain events in the last 30 years involved only one synoptic system per event lasting no more than 3 days, and producing 20–50 mm of precipitation.