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Canadian Tropical Cyclone Season Summary for 1991

1991 Storm Tracks Image
1991 Storm Tracks Image

Tropical Storm Ana   (June 29 to July 5, 1991)

Tropical Storm Ana developed near the Bahamas on July 2, 1991. It moved west-southwestward across south Florida, and then turned northward along the west coast of Florida. Ana continued northeastward towards the St. Augustine area before ceasing to exist to July 5.

Ana developed a maximum wind speed of 81 kilometres per hour (44 knots). It caused no damage and had no direct impact on Canada.

Hurricane Bob  (August 16 to August 29, 1991)

Hurricane Bob originated just southeast of Bermuda on August 16, 1991. It reached maximum wind speeds of 185 kilometres per hour (100 knots). Bob moved along the Atlantic coast and then crossed Rhode Island and Massachusetts, passing near Boston. Bob continued moving, crossing into Maine, New Brunswick and the Gulf of St. Lawrence. It proceeded to pass through northern Newfoundland and the central North Atlantic. Bob finally dissipated near Portugal on August 29.

Hurricane Bob was responsible for $1.5 billion in damage and 18 deaths, including two in Nova Scotia. It also caused power outages in 2.1 million homes. As a result of the storm, strong winds were felt in the Atlantic Canada.

Unnamed   (October 28 to November 2, 1991)

The Storm

A strong extratropical low formed off the coast of Nova Scotia on October 28, 1991. The low moved southward and developed into an extratropical storm 625 kilometres south of Halifax. This storm made a counter clockwise loop and moved northeastward through Nova Scotia and Prince Edward Island. Meanwhile, out in the Atlantic on October 29th, a cold front encountered a dissipating Hurricane Grace and the storm weakened quickly. A new circulation was visible on the GOES photographs late on October 29th forming an extratropical low pressure centre. Moisture that was previously associated with Hurricane Grace moved north-northeastwards and combined with the new low pressure centre. At 1200 UTC on October 30th, this new storm reached its maximum intensity of approximately 975 millibars. At 0355 UTC on October 30th, a buoy 425 kilometres south-southeast of Halifax reported a peak wave height of 30.5 metres. This represents the highest wave height ever measured on the Scotian Shelf. The 30.5 metre max waves reported represent the physical limitations of the instruments on the buoy. The buoy was incapable of reporting a bigger number, so undoubtedly, the max waves were actually bigger.

After reaching peak intensity as an extratropical system, the low turned southward and the central pressure rose to 998 millibars on November 1st. This movement to the south brought the low over the warm waters of the Gulf Stream. At 1200 UTC on November 2nd, the storm was declared by the U.S. National Hurricane Centre to be of hurricane strength. The cyclone accelerated northeastward on November 2nd encountering the much colder waters of the continental shelf and began to weaken rapidly. By the time it reached the Nova Scotia coast near Halifax at 1400 UTC, its maximum sustained winds had diminished to near 40 knots.

Naming This Storm

By the time the tropical system had formed on November 2nd, the extratropical system was on the wane and conditions were improving on the coasts. It was felt by the Canadian Hurricane Centre and the U.S. National Hurricane Centre that naming or re-naming this storm would cause major confusion on the part of the media and the public. The storm is now referred to by meteorologists as 'The Perfect Storm', 'The Unnamed Storm', and 'The Hallowe'en Storm'.


The Hallowe'en 1991 storm caused widespread damage along most of the east coast of North America from Florida to Newfoundland. Many boats, wharves, and seaside properties were damaged or destroyed. Beaches suffered extreme erosion and coastal roads were flooded and damaged. Four incidents took place offshore including the tragic loss of the Andrea Gail, a U.S. swordfishing boat whose normal fishing ground is near 44° North 56° West. On the 31st, she was reported overdue. In the ensuing search, debris from this vessel was found at Sable Island and the crew members were presumed drowned.

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