Trends in Blizzards at Selected Locations on the Canadian Prairies

Climate Change is anticipatedto result in alterations in cyclone activity over the northern hemisphere. Cyclones in their passage across the open prairie of western Canada spawn one of the more extreme weather events that occur in that part of the country; blizzards. Numerous studies of individual blizzards are available. The objective of this study of blizzards is to identify trends in their seasonal occurrence, in seasonal blizzard weather element extremes, and discuss the results in the context of climate change. Criteria used in western Canada to define a blizzard event during the period of study were applied to the archive of hourly weather data for locations within the Prairie Ecozone. Blizzard events were extracted for the period 1953–1997 and analyzed for trends in seasonal occurrence. Results of this analysis are presented which illustrate a significant downward trend for weather observing locations in the more westerly part of the prairies. This trend is consistent with results found by others that indicate a decrease in cyclone frequency over western Canada. No significant trend was found in the more central and eastern locations. No significant trend was evident in seasonal extremes of blizzard weather elements at most locations. Copyright Kluwer Academic Publishers 2003