Three Things to Know: Hurricane Fiona Heads to Canada

1. The Atlantic’s first major hurricane heads for eastern Canada

• Hurricane Fiona is the first major hurricane of the 2022 season, and the storm is currently migrating on a northerly track across the Atlantic Ocean between Bermuda and eastern Canada. The National Hurricane Center (NHC) is forecasting Fiona to make landfall in Canada early Saturday morning (Figure 1). As of Friday, September 23 at 8:00 AM EDT, Hurricane Fiona is a major hurricane, with maximum sustained wind speeds of 125 mph (201 kph). Meteorologists expect Fiona to weaken slightly before making landfall as it will pass over colder ocean temperatures. Nevertheless, the storm is still expected to pack a powerful punch in eastern Canada with hurricane-force winds up to 115 mph (185 kph).

Figure 1: Hurricane Fiona forecasted track and strength through Wednesday (NHC 8 AM AST Advisory 36A).

• The NHC forecasts 3 – 6 inches (75 – 150 mm) of rain across Nova Scotia, Prince Edward Island and western Newfoundland, with isolated spots receiving up to 10 inches (250 mm) of rain. Eastern Newfoundland, Quebec and New Brunswick may see 1 -5 inches (25 – 125 mm) of rain.
• The potential storm surge from Hurricane Fiona indicates a high probability of substantial coastal flooding and destructive waves along the Nova Scotian coastline.

2. Hurricane-force winds over 74 mph to blast many Nova Scotia buildings

• Canada is familiar with tropical cyclone activity in spite of its northerly position relative to the tropics. Since the mid-19th century, there have been 240 landfalling “hurricanes” in Canada.^[1] However, by the time tropical cyclones reach the northern latitudes of Canada, they are generally considered remnant low-pressure systems or extratropical cyclones. These features are no longer powered by warm ocean temperatures like tropical storms and cyclones but rather by northern weather systems. Still, the extratropical storms that reach Canada can still bring hurricane-force winds that reach speeds greater than 74 mph.
• According to the NHC, hurricane-force winds over 74 mph (the minimum speed for a Category 1 storm) can produce some damage, even to well-constructed homes. Roof and siding damage are most likely with winds at such a speed. Once winds reach Category 2 status (> 96 mph), the potential for major damage is much higher with scenarios such as uprooted trees and near-total power loss becoming possible.^[2]
• Eastern Nova Scotia is expected to bear the brunt of Hurricane Fiona’s severe winds when landfall occurs this weekend. According to the NHC (as of Friday, September 23 at 8:00 AM EDT) and the Canada Open Database of Buildings^[3], nearly 30,000 buildings in Nova Scotia have a 50% or greater probability of experiencing hurricane-force winds (Figure 2).

Figure 2: Probability of hurricane-force winds in Nova Scotia (NHC 8 AM AST Advisory 36A).

3. Nova Scotia faces widespread flood risk due to heavy rain and storm surge

• From 1900 to 2016, flooding in Canada has outranked all other types of natural disaster events in both frequency and monetary losses. ^[4] In addition, losses from flooding have been trending upwards over the past 30 years. In the past, public disaster assistance for flood losses were primarily provided by the federal and local governments.
• The current precipitation and storm surge forecasts for Nova Scotia indicate that widespread flooding is likely. Much of the exposure in Nova Scotia is concentrated along rivers or the coast which are areas of elevated flood risk (Figures 3 and 4). CoreLogic estimated the flood risk for each building (in the Canada Building Open Database) in Nova Scotia. The results show that a significant number of these buildings are at a moderate to very high flood risk (Table 2).

Figure 3: CoreLogic Canada Flood Risk Score in Halifax, Nova Scotia.

Figure 4: CoreLogic Canada Flood Risk Score in Sydney, Nova Scotia. Source: CoreLogic 2022

Table 1: Approximate number of buildings in Nova Scotia by CoreLogic Canada Flood Risk Score.

 

• The CoreLogic Flood Risk Score for Canada includes coastal, flash and riverine flooding. The scores leverage detailed hydrological and hydraulic modeling analyses, which were validated against river gauge data, local engineering studies and flood maps. The flood risk scores account for local flood defenses such as levees and sea walls.

Stay tuned: CoreLogic Event Response is continuing to monitor impacts from Hurricane Fiona. All updates will be available on www.hazardhq.com.

^[1] Rocha, Roberto, These are the hurricanes that hit Canada since 1900. (CBC 2017). https://www.cbc.ca/news/canada/montreal/hurricane-history-canada-1.4284076. Accessed September 21, 2022.

^[2] National Hurricane Center, Saffir-Simpson Hurricane Wind Scale. (NHC 2022). https://www.nhc.noaa.gov/aboutsshws.php#:~:text=The%20Saffir%2DSimpson%20Hurricane%20Wind,Scale%20estimates%20potential%20property%20damage. Accessed September 22, 2022.

^[3] Statistics Canada, The Open Database of Buildings. (Statistics Canada 2022). https://www.statcan.gc.ca/en/lode/databases/odb. Accessed September 21, 2022.

^[4] Public Safety Canada, The Canadian Disaster Database. (Public Safety Canada 2022). Accessed September 21, 2022.