Major Cold-Season Precipitation Events at Iqaluit, Nunavut

  • Gabrielle Gascon
  • Ronald E. Stewart
  • William Henson
Keywords: Canadian Arctic, autumn storms, extreme events, Iqaluit, precipitation, snow

Abstract

This study focuses on cold-season (October-April) precipitation events at Iqaluit, Nunavut, that exceed the 97th percentile of daily corrected precipitation accumulation. This corresponds to a threshold of 9.5 mm. The characteristics of 194 major precipitation events are described for the 1955 - 96 period. On the basis of NCEP-NCAR and NARR reanalysis data, these events were classified into four storm tracks: south, west, Atlantic, and other. South- and Atlantic-originating systems tended to be associated with the most severe events. The duration and precipitation rate of the events, rather than the speed of motion, were critical factors influencing precipitation accumulation. Snow was the dominant precipitation type. Surface warm frontal passage was a common tropospheric feature, and the topography was important in terms of altering surface wind direction during the events. No significant trend in the occurrence of major precipitation is evident.
Published
2010-09-01