EES Departmental Seminar: A Major Hurricane in the Little Ice Age

Speaker: John Dickie

Title: A Major Hurricane in the Little Ice Age

Abstract: Natural climate variability is important for modelling midlatitude hurricane risk under a warming climate yet models focus on the brief instrument-based record. Given their destructive impact, it is important to define how Atlantic cyclones fit into longer trends. Historical and proxy data have the potential to extend the record by centuries. The violent 1757 Louisbourg Storm off Nova Scotia during the Seven Years’ War was characterized by extracting quantitative attributes from historical records preserved in logs from the vessels of two powerful fleets caught in the hurricane. Peak wind speeds and storm surge at two coastal archaeological sites were compared to modern Atlantic hurricanes, including an extratropical cyclone in 2000 and a Category 2 Hurricane in 2003 (Juan) that crossed the same bathymetry. The results indicate it was a major hurricane, making it much stronger than modern midlatitude storms, yet this is at odds with colder climate conditions during the Little Ice Age that normally suppress hurricane energy. Ironically, the coldest years of that period were also the stormiest and saw some of the most destructive Atlantic hurricanes in history. The Louisbourg Storm’s intensity may have been triggered by the expansion of cold, baroclinic continental air associated with the annual onset of fall cooling that occurred earlier during the Little Ice Age than today. An assessment of hurricane season in 1700-1880, however, shows it was identical to the modern season defined by NOAA (1944-2020). This increased the probability for a strong midlatitude hurricane to meet strongly baroclinic conditions capable of triggering explosive extratropical transition. The hurricane struck Nova Scotia during a multidecadal 2.5 degree latitudinal southward shift in the population of 66 hurricanes yet damage to the British fleet from this one storm event almost changed the balance of power in North America.

Profile: John Dickie holds B.Sc. (Hons.), M.Sc. (Dalhousie University), B.Ed. (University of Toronto) and MBA (St. Mary’s University) degrees. An Adjunct to the Faculty of Graduate Studies (Dalhousie) and associate of the Basin and Reservoir Lab (Dalhousie Earth and Environmental Sciences), John has worked as a geologist on mineral projects in the Canadian Cordillera, USA, Mexico and South Pacific, and in oil and gas projects including the Sable Offshore Energy Project offshore Nova Scotia. He joined the Province of Nova Scotia to focus on industrial benefits, offshore supplier development, building training and research capacity at post-secondary institutions and marketing Nova Scotia’s strengths in global markets. He was part of the leadership team behind OERA, Efficiency Nova Scotia, FORCE, Carbon Capture and Storage NS and others to facilitate Nova Scotia’s energy transition. John is a PADI Rescue and IANTD Technical diver with a Nautical Archaeology Society (UK) certificate in underwater archaeology and over 25 years’ experience. John has written many industry reports, developed government policy and programs, published scientific research and a book on the 1797 wreck of HMS Tribune in Nova Scotia, and has contributed to collections at the SS Atlantic Heritage Interpretation Park in Terence Bay Nova Scotia and at the Maritime Museum of the Atlantic, Halifax, where he has presented on HMS Tribune and the Legend of Joe Cracker. Interest in hurricanes grew from shipwreck diving, experiencing 75’+ wave heights of the 2000 ‘superbomb’ offshore, and a daughter born during Hurricane Juan in 2003




Format: In-person
Milligan Room (8th floor LSC Biology Wing)