Freezing precipitation in Canada

Renewed interest in freezing precipitation processes and their cause have resulted in a requirement for an updated detailed climatology of freezing precipitation in Canada. Previous work in this area was very limited in terms of the period of record and the extent of the analysis. In this study national maps were prepared of occurrence frequencies of freezing rain, freezing drizzle and freezing precipitation. Each precipitation type was stratified by month, and stratified again by either wind direction or time of day. Unstratified results were compared with previous work and both similarities and differences were noted. An analysis of wind direction stratification maps for stations around Hudson Bay demonstrated the effect of large features on the occurrence of freezing precipitation. The detailed climatology of freezing precipitation in Atlantic Canada shows that production mechanisms are closely linked with local effects. The duration of freezing precipitation events is usually 1-2 hours, but durations greater than 8 hours are not uncommon. Freezing precipitation usually occurs with surface temperatures between 0 degrees and -5 degrees C.