The extratropical transition of Hurricane Igor and the impacts on Newfoundland

Abstract

There is a tendency to equate the word “hurricane” with the tropical regions of the world. Many residents do not recognize the danger and risks that occur when a tropical cyclone reaches colder subtropical waters and undergoes extratropical transition. Atlantic Canada, particularly the island of Newfoundland, is most at risk from extratropical transitions. The circumstances, location and dynamics of extratropical transitions in the North Atlantic have not been extensively studied. Consequently, forecasters continue to call approaching storms “hurricanes,” when most are extratropical cyclones by the time they reach Atlantic Canada. Newfoundland, in particular, has suffered devastating impacts from extratropical transition, notably Igor in 2010. Igor impacted Newfoundland as a Category 1 hybrid system, which was still undergoing extratropical transition. Igor was an example of a classic Cape Verde cyclone. Flooding was a severe problem, destroying property and roads and isolating communities. Total damages were estimated to be at least $110 million CAD with some values reaching as high as $200 million CAD. Fire and emergency services-Newfoundland and Labrador, the government of Canada, climatologists and meteorologists will benefit from a deeper understanding of extratropical transitions. Better forecasts could warn a given population of when and where a transition could take place and how best to prepare for the consequences.