The History of Extratropical Transition in Canada: Impacts, Research, and Prediction

Just over 150 years ago, a hurricane of historic proportions impacted New England and the Canadian Maritimes. The so-called Saxby Gale was predicted by a Royal Naval Officer in London England nearly a year in advance, following his analysis of the alignment of the earth and the moon and a very large predicted tide.

This storm may have been the first documented case of an extreme extra-tropical transition of a hurricane, with significant property damage and loss of life in New England from freshwater flooding, and in the Maritimes from strong winds, high waves and storm surge.

In 1954, the most notable hurricane in Canada’s largest city, Toronto, resulted in the loss of 81 residents and left 4000 homeless from flooding after a 200mm rainfall. Then 31 years later, Hurricane Gloria threatened to take a similar track as Hazel. A media frenzy ensued, with the Canadian public glued to Cable News, following closely the forecasts from the US National Hurricane Centre. The impacts were much less than feared, with a public perception of a blown forecast. Given the lack of a hurricane related products and services, the Government of Canada made the decision to develop it’s own Canadian Hurricane Centre.

This presentation will highlight the steps taken to formally develop hurricane forecast and research expertise in Canada, with a focus on the challenges related to extratropical transition. Observation research included perhaps the first dedicated series of aircraft investigations into extratropical transitioning storms using a Convair 580 research aircraft. Forecast research efforts included a focus on numerical weather prediction. Ultimately, within the auspices of the WMO Tropical Research Program, the joint effort of scientists and forecasters from the international community has helped advance the understanding and prediction capability of the Canadian Hurricane Centre such that it is recognized globally for its leadership in Extratropical Transition.