Tornado climatology of Canada revisited: Tornado activity during differentphases of ENSO

Tornadoes are a significant hazard in some parts of Canada, particularly in the southern Prairie provinces and southwestern Ontario, though they are n ot as common as in some parts of the US. Since the early 1980s, the regiona l weather offices in Canada have been recording tornado event information o n a routine basis, and thus data exists that can be used to update older an alyses of tornado frequencies. On average, about 60 tornadoes are reported each year, though many doubtless occur that are not observed or recorded in the Environment Canada records. An analysis of tornado frequencies with El Nino-Southern Oscillation (ENSO) events suggest that the cooler La Nina ev ents tend to suppress tornadic activity, while El Nino events tend to enhan ce it (though there are exceptions to this trend). Copyright (C) 2001 Crown in the right of Canada. Published by John Wiley & Sons, Ltd.