Eastern US and Canada suffer major damage after Hurricane Debby
In early August, Hurricane Debby struck Florida with the remnants moving northwards through the eastern United States and into eastern Canada (Guardian, 2024a). At least eight people died in the United States and one person in Canada’s Quebec province due to heavy rains and flash flooding (Guardian, 2024b; Global News, 2024a). Based on preliminary estimates from Catastrophe Indices and Quantification Inc. (CatIQ), the storm caused nearly $2.5 billion CAD ($1.84 billion USD) in insured damage (Reinsurance News, 2024).
Event Overview
Birth of Hurricane Debby
The fourth named storm of the 2024 Atlantic hurricane season, Hurricane Debby began life as a tropical depression on 2 August, before strengthening to a tropical storm (3 August) and then a category 1 hurricane (4 August). It first made landfall on 5 August near Steinhatchee, Florida, moved offshore into the Atlantic Ocean on 6 August, before making a second landfall on 8 August near Bulls Bay, South Carolina (NESDIS, 2024).
Figure 1: Satellite-observed rainfall for the eastern US and Canadian coast between 4th and 12th Aug 2024. Rainfall data source: NASA GPM 3-hour rainfall accumulation (2024). Animation produced by JBA Risk Management (2024).
Hurricane Debby caused widespread flooding in the south-eastern United States with 35 million people placed under flood warnings from South Carolina to Vermont (Spectrum News 1, 2024). The storm uprooted trees and damaged properties along its path, with 300,000 customers suffering power outages in the south-eastern US (NESDIS, 2024).
Decaying of Debby into post-tropical cyclone storm
On 8 August, Debby was downgraded to a tropical depression and then a post-tropical cyclone (NESDIS, 2024). The remnants of storm Debby combined with a low-pressure system over Canada’s Great Lakes caused torrential rainfall in eastern Ontario and southern Quebec on 9 and 10 August (Global News, 2024b). Montreal, Quebec, received upwards of 150mm of rain in a single day, breaking the previous daily record set in November 1996 (CBC, 2024; Lethbridge News Now, 2024). Elsewhere in Quebec, up to 100mm of rain fell in Gatineau and more than 220mm in Lanoraie, whilst Ottawa, Ontario, received around 75mm (Global News 2024b).
Figure 2: Satellite-observed rainfall in the Montreal area between 8th and 12th Aug 2024. Rainfall data source: NASA GPM 3-hour rainfall accumulation (2024). Animation produced by JBA Risk Management (2024).
More than 50 municipalities across Quebec were impacted by the event, with eight declaring states of emergency (Global News, 2024a). At its peak, at least half a million homes were left without power (Global News, 2024a). Across the province, nearly 100 roads were submerged and several highways and tunnels were closed, leaving more than 1,500 homes isolated (Global News, 2024a; Global News 2024b). Hundreds of people were evacuated and Montreal’s fire department received more than 600 calls as the authorities used boats to carry out rescue operations. Several landslides were also reported in the Laurentian Mountains (CBC News, 2024).
Historical events
Debby is the second ex-hurricane to hit eastern Canada this year following Hurricane Beryl in mid-July (Canadian Underwriter, 2024). Beryl’s remnants left their mark in Canada after transforming into a post-tropical cyclone bringing about heavy rains, with rainfall totals of up to 50mm, flooding major highways and public transport routes in southern Ontario and Quebec (The Weather Network, 2024). Further impacts of Beryl, and other similar past events in the region can be seen in the table below.
This report is accompanied by a flood footprint covering flooding in Canada as a result of post-tropical cyclone Debby - detailing extents and depths of the flooding in areas affected. Download it via our Client Portal or request a copy by emailing eventresponse@jbarisk.com.
References
AP News, 2023. Hurricane Beryl makes landfall, spawns tornadoes. [Online]. Available at: https://apnews.com/article/hurricane-beryl-tornado-f7169969463c301769715e9d81bf6bde [Accessed: 25 September 2024]
BBC News, 2020. At least five people killed as heavy rains cause flooding in the US and Canada. [Online]. Available at: https://www.bbc.co.uk/news/world-us-canada-53645297 [Accessed: 25 September 2024]
CBC, 2024. Southern Quebec still struggles with remnants of tropical storm Debby. [Online]. Available at: https://www.cbc.ca/news/canada/montreal/rain-tropical-storm-debby-southern-quebec-1.7291210 [Accessed 24 September 2024]
Canadian Geographic, 2018. Lessons learned from the Ice Storm of 1998. [Online]. Available at: https://canadiangeographic.ca/articles/lessons-learned-from-the-ice-storm-of-1998/ [Accessed: 24 September 2024]
Canadian Underwriter, 2024. Quebec faces Debby’s wrath. [Online]. Available at: https://www.canadianunderwriter.ca/brokers/record-rainfall-drenches-quebec-adjusters-respond-to-flooding-1004249260/ [Accessed 25 September 2024]
FloodList, 2017. Spring floods in Ontario and Quebec caused millions in insured damage. [Online]. Available at: https://floodlist.com/america/canada-spring-floods-ontario-quebec-caused-millions-insured-damage [Accessed: 25 September 2024]
Global News, 2023. Montrealers remember the Ice Storm of 1998. [Online]. Available at: https://globalnews.ca/news/9387886/montrealers-remember-ice-storm-1998/ [Accessed: 24 September 2024]
Global News, 2024a. Debby fallout: Quebec faces flooded homes, roads after record-setting storm. [Online]. Available at: https://globalnews.ca/news/10694117/montreal-debby-flooding-aftermath/ [Accessed 24 September 2024]
Global News, 2024b. Montreal drenched in record-breaking rain as tropical storm Debby’s remnants hit Canada. [Online]. Available at: https://globalnews.ca/news/10692242/montreal-rain-record-tropical-storm-debby-eastern-canada/ [Accessed 24 September 2024]
Guardian, 2024a. Weather tracker: Storm Debby leaves power cuts and flooding in wake. [Online]. Available at: https://www.theguardian.com/environment/article/2024/aug/12/weather-tracker-storm-debby-leaves-power-cuts-and-flooding-in-wake [Accessed 24 September 2024]
Guardian, 2024b. Storm Debby spirals to US north-east with forecasts of tornadoes and floods. [Online]. Available at: https://www.theguardian.com/world/article/2024/aug/09/storm-debby-us-north-east [Accessed 24 September 2024]
Insurance Journal, 2020. Estimated total insured losses from Hurricane Isaias will exceed $4 billion. [Online]. Available at: https://www.insurancejournal.com/magazines/mag-features/2020/08/24/579884.htm [Accessed: 25 September 2024]
Lethbridge News Now, 2024. Tropical storm Debby remnants brings significant rainfall to Montreal, Eastern Canada. [Online]. Available at: https://lethbridgenewsnow.com/2024/08/10/tropical-storm-debby-remnants-brings-significant-rainfall-to-montreal-eastern-canada/ [Accessed 24 September 2024]
NESDIS, 2024. A Look Back at Debby. [Online]. Available at: https://www.nesdis.noaa.gov/news/look-back-debby [Accessed 24 September 2024]
Reinsurance News, 2024. Hurricane Debby caused $2.5bn in insured damage in Quebec: CatIQ. [Online]. Available at: https://www.reinsurancene.ws/hurricane-debby-caused-2-5bn-in-insured-damage-in-quebec-catiq/ [Accessed 24 September 2024]
Spectrum News 1, 2024. Debby made landfall as a hurricane and brought flooding across the Southeast. [Online]. Available at: https://spectrumlocalnews.com/tx/south-texas-el-paso/weather/2024/07/31/tracking-debby [Accessed 24 September 2024]
The Weather Network, 2017. This day in weather history: April 7, 2017 – Ontario and Quebec flooding. [Online]. Available at: https://www.theweathernetwork.com/en/news/weather/severe/this-day-in-weather-history-april-7-2017-ontario-and-quebec-flooding [Accessed: 25 September 2024]
The Weather Network, 2024. Heavy rain pushes in as remnants from Beryl prompt widespread warnings in Ontario, Quebec. [Online]. Available at: https://www.theweathernetwork.com/en/news/weather/forecasts/heavy-rain-pushes-in-as-remnants-from-beryl-prompt-widespread-warnings-in-ontario-quebec (Accessed: 25 September 2024).
ThoughtCo, 2019. Canadian ice storm in 1998. [Online]. Available at: https://www.thoughtco.com/canadian-ice-storm-in-1998-508705 [Accessed: 25 September 2024]
