May 2022 Canadian derecho
Date(s)May 21, 2022
Duration9 hours
Track length620 mi (998 km)
Peak wind gust  (measured)89 mph (143 km/h; 39.8 m/s) (Magog, Quebec, Canada)
Peak wind gust (est.)118 mph (190 km/h; 52.8 m/s) (Ottawa, Canada)[1]
Tornado count4[2]
Strongest tornado1 EF2 tornado
Fatalities12[3]
Damage costsC$ 875 million[4] ($780 million USD)
Types of damage Widespread damage to residential and commercial property and public utility infrastructure
Areas affectedSouthern Ontario, southern Quebec
1Most severe tornado damage; see Enhanced Fujita scale

The May 2022 Canadian derecho was a high-impact derecho[5] event that affected the Quebec City-Windsor Corridor, Canada's most densely populated region, on May 21, 2022. Described by meteorologists as a historic derecho and one of the most impactful thunderstorms in Canadian history,[6][7] winds up to 190 km/h (120 mph) as well as around four tornadoes caused widespread and extensive damage along a path that extended for 1,000 kilometres (620 mi).

Three cities across southern Ontario declared a state of emergency. At least twelve people were killed, mostly by falling trees.[8] Power outages affected an estimated 1.1 million customers, and thousands were still without power a week after the storm.[9] Hydro Ottawa described the damage dealt to its power distribution system as more severe than the 1998 ice storm. The storm was the sixth-costliest event in Canadian history.[10]

According to an estimate published on June 15 by the firm Catastrophe Indices and Quantification (CatIQ), the insured damage would amount to C$875 million, that is, C$720 million in Ontario and C$155 million in Quebec. This ranks the derecho as the sixth-costliest natural disaster in Canada in terms of insurance claims.[4]

Background

Derecho frequency for the affected region

Derechos in southern Canada are not common. Derechos affecting this region typically develop in the U.S. Midwest and affect only a small part of the Quebec City-Windsor Corridor.[11] This was the first event in Canada since 1999.[12] In Southern Ontario, a derecho can be expected about once every year, to about once in every four years depending on the area.[11]

Typically, derechos anywhere in this area form during mid-summer. These derechos usually occur when a hot and muggy air mass covers the Midwest and Ohio Valley, since the stronger derechos in this region tend to develop on the northern boundary between the hot, humid air and cooler, drier air where there is also an elevated mixed layer (EML).[13][14][11]

Most derechos in Canada are progressive derechos which skirt the northern edge of a heat wave high pressure area, or hybrid derechos which are similar to progressive derechos, but arise ahead of a cold front.[14] Tornadoes which accompany these types of derechos are usually Quasi-Linear Convective System (QLCS) tornadoes which are embedded in the bow front.[14][15]

Meteorological history

A persistent May heat wave in the U.S. expanded sporadically to include southern Ontario and Quebec throughout May, resulting in unseasonably warm temperatures more typical of July.[16] After a brief respite, the heat returned on May 19, 20, and 21.[17] At 11 am, Toronto Pearson Airport hit 29.3 °C (84.7 °F), three degrees shy of the record for that date, with a humidex of 36 °C (97 °F).[18] Ottawa-Gatineau hit 31.5 °C (88.7 °F) at 2 pm, one degree shy of the record for that date, with a humidex of 38 °C (100 °F).[19] A sharp cold front was expected to bring thunderstorms through the region on Saturday, prior to a precipitous drop in temperature potentially resulting in subsequent frost.[20][21][22]

The system first formed south of Chicago.[23] On Saturday morning at 10:37 am EST, thunderstorms with significant wind developed in Macomb and St. Clair counties in Michigan. The wind of these storms snapped some trees, mostly in St. Clair County, but this cluster of thunderstorms had not yet formed a bow echo.[24]

The derecho developed near Sarnia at 9:30 am. By 10:45 am when the storms hit London, the derecho had coalesced into a bow front roughly 100 km (62 mi) wide[25] and had developed wind speeds of close to 100 km/h (62 mph). The bow front continued to widen and intensify east of London, roughly following a corridor between Highway 401 and Highway 7 in Ontario, and then along the Autoroute 20 in Quebec.

The storm moved east at an average 100 km/h, striking Toronto at 1:00 pm, Ottawa at 3:50 pm, Montreal at 5:30 pm, and Quebec City at 6:30 pm.[26][25] The weather changed very rapidly as the derecho approached. At Pearson International Airport, in the period between 12:52 pm and 1 pm, gust wind speeds went from 72 km/h to 120 km/h.[27]

The bow echo retained its structure for nine hours, and covered a total track length of 1,000 km (620 mi). It weakened over south-central Quebec, and dissipated in the Atlantic Canada region by early Sunday morning.

Straight line wind speeds

The highest reported wind gust of 144 km/h (89 mph) was recorded at Lake Memphremagog, Quebec.[28] In Ontario, Kitchener/Waterloo Airport recorded a peak wind gust of 132 km/h (82 mph).[29][30][31] Most of the weather stations along the derecho's path recorded wind gusts near or above 100 km/h (62 mph), including the Greater Toronto Area, Ottawa, Trois-Rivières, and Quebec City.[32]

A storm survey from the Northern Tornadoes Project reported a severe downburst in parts of southern Ottawa. Its windspeeds reached up to 190 km/h (120 mph).[26][33][34]

A gust of 121 km/h (75 mph) at Pearson International Airport set a May record, and is the fifth strongest wind gust ever recorded at that location.[35]

Tornadoes

An EF2 tornado which was embedded in the leading edge of the derecho[15] struck Uxbridge, Ontario at 1:15 pm.[26][36][37] Two EF1 QLCS tornadoes were confirmed in London, Ontario.[38] Another EF2 tornado was detected in the Lake Scugog area .[2]

Prediction

Alert Ready message on Android devices, issued for Gatineau, Québec

For the first day of the Victoria Day long weekend, atmospheric instability was forecast throughout Michigan's south peninsula, the Ohio Valley, southern Ontario and southern Quebec. Most of southern Ontario south of the 401 was assigned a marginal risk of severe weather. Tornadoes were predicted to be possible in eastern Ontario into southern Quebec in the afternoon.[39]

Environment Canada issued weather statements for Sarnia and Windsor at 9:43 am,[40] which was upgraded for Sarnia to a severe thunderstorm warning at 10:25 am.[41] Severe thunderstorm watches for the London area followed at 10:41 am,[42] upgraded to a severe thunderstorm warning at 11:08.[43] The alert mentioned possible strong wind gusts up to 100 km/h (62 mph), along with nickel-sized hail.

Severe thunderstorm watches were issued for points eastward of London at 11:19 am.[44] These were later upgraded to severe thunderstorm warnings.

Additionally, after the derecho hit London, Environment Canada issued an emergency alert for regions in Ontario and Quebec along the path of the storm, with alerts going out over cellphones, television, and radio.[45] This was the first time Environment and Climate Change Canada (ECCC) issued an Alert Ready message for a Severe Thunderstorm Warning.[46]

Impact

Downed utility lines and trees on Brock Street (Uxbridge)

The derecho impacted roughly 15.6 million people, representing about 41 percent of Canada's population.[6] Strong winds downed over 1,900 hydro poles, five metal transmission towers, and numerous trees along the path of the derecho.[47][48][49][50] The damage included the downing of over 300 power poles in Ottawa.[51][52] In Quebec, the Laurentides, Lanaudière, and l’Outaouais were most affected.[53]

Eleven people were killed in eastern Ontario by windthrown trees or branches.[54][48] Another person was killed after their boat sank in the Ottawa River near Gatineau, Quebec.[55][48] Most of the victims were engaged in recreational activities on the holiday weekend.[56]

Extensive damage was inflicted upon homes and buildings by wind and falling trees,[57][48] with some homes completely destroyed.[54] The communities of Stittsville, Hunt Club, Navan, and Sarsfield, where a church steeple was toppled and farms were destroyed, were the worst hit in the Ottawa area. The Saint-Fidèle church in Fassett also lost its steeple.[58] In Rockland, a 30-ton silo was moved a foot and had its roof torn off.[59]

The destroyed church steeple in Sarsfield, Ontario

Power outages affected over 1.1 million customers, with 586,000 Hydro One outages in Ontario and 550,000 Hydro-Québec outages.[60][61] In Ottawa, the airport and water treatment plant lost grid power for more than 24 hours.[62] In a letter to Ottawa mayor Jim Watson, Hydro Ottawa described the damage dealt to its power distribution system as "beyond comprehension" and more severe than the 2018 tornadoes or the 1998 ice storm.[63]

Rail and air transportation were significantly affected. Trains along the Windsor-Ottawa corridor were delayed by hours due to trees on the tracks, with some passengers having to be bussed to their destinations. Flights were delayed at Pearson International Airport, while a small plane at London International Airport was flipped over despite being strapped down. Subway trains in Toronto were stalled after one train ran over a downed tree.[64]

Aftermath

Downed power lines on Woodroffe Avenue (Ottawa)

The storm was the sixth-costliest event in Canadian history.[10]

The municipal governments of Uxbridge and Clarence-Rockland declared local states of emergency on May 21. Peterborough declared a state of emergency on May 25.[65][66] Ottawa did not declare a state of emergency; mayor Watson stated that the city had enough resources to handle the situation and that declaring a state of emergency would only amount to a symbolic gesture.[67]

Due to the extensive infrastructure damage and large number of fallen trees, at least a quarter of outages in the hardest hit areas continued more than four days.[68][62] Ottawa Hydro restored power to just over half its customers after one week.[69] Three hundred Ottawa-area customers were still without power at the beginning of June.[70] Some rural and remote Hydro One customers in the Perth, Bancroft, and Tweed areas remained without power for multiple weeks.[71][72]

Forty percent of Quebec hydro outages continued two days after the storm hit.[73][74] Five percent of customers lost power for more than a week.[75]

Rogers and Bell reported widespread internet and television service outages in Ottawa and the surrounding area, but did not provide information on when service would return.[76] Outages were also reported across southern Ontario.

Due to the Victoria Day holiday, most schools were able to open normally on Tuesday, although a few remained closed because they were still without power.[68]

The National Capital Commission (NCC) greenbelt lost thousands of trees during the derecho, with every greenbelt sector affected. It was the first time the entire NCC greenbelt was closed. Some trails were still closed as of August 25. Red pine logs resulting from the fallen trees can be salvaged at no cost by the public, requiring only a land access permit.[77]

Provincial election

I don’t think our contingency plans have ever gone to the extent of massively losing power for a considerable number of days in a wide swath of returning offices.

- Greg Essensa, chief electoral officer, Ontario[78]

Advance poll voting for the 2022 Ontario provincial election was disrupted by the power outages and by falling trees, particularly in the London, Kitchener-Waterloo, Brampton, Peterborough, and Ottawa regions. Forty-nine advance polls closed after they lost power or were damaged by falling trees or wires, either temporarily or for the day.[78] Some advance poll locations had to be removed or changed, but all locations retained at least one advance poll per riding.[78][79] One of the London tornadoes brushed the Stronach Community Recreation Centre, where one of the London—Fanshawe advance polls was based.[80]

Provincial elections in Ontario are computerized, but are designed to be used with paper ballots and contingency ballot boxes, as well as hardcopy backups of the electors list.[81] Many polls lacking power were able to operate with natural light.[82] No votes were lost.[78]

Government assistance

At the federal level, Prime Minister Justin Trudeau offered federal aid to severely affected communities.[73]

Locally, Ottawa and Peterborough opened respite centres, with showers and charging stations.[60][68] Tweed opened a water filling station at its municipal office.[83] Ottawa and Gatineau also offered emergency food aid.[83]

To assist small business owners who had been severely affected by the derecho, Renfrew County offered relief loans to small businesses at 0% interest, with deferred payments for one year.[84]


See also

References

  1. ↑ Woods, Michael (25 May 2022). "Ottawa storm winds reached 190 km/h: researchers". CTV News. Retrieved 25 May 2022.
  2. 1 2 "May 21 derecho update #1 of 2: one more EF2 tornado". www.uwo.ca. Northern Tornadoes Project. 2022-06-27. Retrieved 2022-07-11.
  3. ↑ "Maps for May 21st derecho and all 2022 ground surveys". uwo.ca. Northern Tornadoes Project. 25 November 2022. Retrieved 22 May 2023.
  4. 1 2 Canadian Press (June 15, 2022). "Plus de 875 millions de dollars de dommages assurés". La Presse (in French). Retrieved June 15, 2022.
  5. ↑ "What is a 'derecho'? Climatologist explains Saturday's powerful storm". CTV News. 2022-05-22. Retrieved 23 May 2022.
  6. 1 2 Scott, Chris (23 May 2022). "Nearly half of Canada's population hit by derecho, why it was harmful". The Weather Network. The Weather Network. Retrieved 24 May 2022.
  7. ↑ "Deadly derecho affected nearly half of Canada's population, spawned EF2 tornado". AccuWeather. 25 May 2022. Retrieved 2022-05-29.
  8. ↑ "11th person dies from weekend storm, tens of thousands Ontarians still without power". CP24.com. Bell Media. 26 May 2022. Retrieved 27 May 2022.
  9. ↑ "Two more tornadoes confirmed in Ontario from destructive derecho". The Weather Network. The Weather Network. 28 May 2022. Retrieved 29 May 2022.
  10. 1 2 "May 21 storm ranked 6th most expensive natural disaster in Canadian history: IBC". 15 June 2022.
  11. 1 2 3 "Understanding a Derecho: What is it?" (PDF). NOAA. Archived from the original (PDF) on 2014-12-22.
  12. ↑ "CBC News".
  13. ↑ "Derecho: Rare but dangerous storm system you should know about".
  14. 1 2 3 "Facts About Derechos - Very Damaging Windstorms".
  15. 1 2 "Squall Line/Bow Echo/QLCS".
  16. ↑ "'Just a head-shaker': Unexpected May heat wave blankets Ottawa". CBC News. 2022-05-16. Archived from the original on 2023-03-19.
  17. ↑ "At least 11 dead in wake of Michigan tornado, Canada derecho » Yale Climate Connections". 23 May 2022.
  18. ↑ "Hourly Data Report for May 21, 2022 - Climate - Environment and Climate Change Canada". 31 October 2011.
  19. ↑ "Historical Data - Climate - Environment and Climate Change Canada". 31 October 2011.
  20. ↑ "Shorts to coats: A wild forecast for Canada's unofficial start to summer". 18 May 2022.
  21. ↑ "Thunderstorms to hit Montreal during hot, humid weekend; more pleasant for holiday Monday". 20 May 2022.
  22. ↑ "First bout of 30 degree heat could hit Toronto by the long weekend". 17 May 2021.
  23. ↑ Bernstein, Jaela (May 25, 2022). "What's a derecho and why is it so destructive? The science behind this powerful storm". CBC. Retrieved June 18, 2022.
  24. ↑ "Storm Prediction Center 20220521's Storm Reports".
  25. 1 2 "Not everyone's phone got that storm alert. It's not clear why". CBC News. 2022-05-26. Archived from the original on 2023-03-19.
  26. 1 2 3 "Weather Summaries - Environment Canada". 6 August 2013.
  27. ↑ "Environment Canada confirms EF2 tornado was part of deadly Ontario storm". 24 May 2022.
  28. ↑ "At least 11 dead in wake of Michigan tornado, Canada derecho » Yale Climate Connections". Yale Climate Connections. May 23, 2022.
  29. ↑ "Three dead, more than 350,000 without power after powerful storm rips through Ontario". CP24. 21 May 2022. Retrieved 23 May 2022.
  30. ↑ "At least eight dead, thousands without power after storm". CP24. 22 May 2022. Retrieved 23 May 2022.
  31. ↑ "Storm leaves at least 10 people dead, many powerless". CP24. 23 May 2022. Retrieved 23 May 2022.
  32. ↑ Pelmorex Weather Networks Inc. "Nearly half of Canada's population hit by derecho, why it was harmful". www.theweathernetwork.com.
  33. ↑ "Ottawa storm winds reached 190 km/H: Researchers". 25 May 2022.
  34. ↑ "EF2 downburst in Ottawa".
  35. ↑ "Derecho leaves roughly 1,000 km of damage, fatalities in its wake".
  36. ↑ "Tornado confirmed in Ontario after destructive long-weekend storm". The Weather Network. Oakville ON: Pelmorex Corp. 24 May 2022. Retrieved 24 May 2022.
  37. ↑ "Uxbridge ON EF2 tornado".
  38. ↑ "Two EF1 tornadoes in London, ON". www.uwo.ca. Retrieved 2022-05-27.
  39. ↑ "Storm Prediction Center May 21, 2022 0600 UTC Day 1 Convective Outlook".
  40. ↑ @ECAlertON147 (May 21, 2022). "09:43 EnvCanada issued #Weather statement #Sarnia #ONStorm" (Tweet) – via Twitter.
  41. ↑ @ECAlertON147 (May 21, 2022). "10:25 EnvCanada issued #Thunderstorm warning #Sarnia #ONStorm. Details:. Weather #Radar:" (Tweet) – via Twitter.
  42. ↑ @ECAlertON137 (May 21, 2022). "10:41 EnvCanada issued #Thunderstorm watch #London #ONStorm" (Tweet) – via Twitter.
  43. ↑ "Alerts for: London - Middlesex - Environment Canada".
  44. ↑ @ECAlertON118 (May 21, 2022). "11:19 EnvCanada issued #Thunderstorm watch #Ottawa(KanataOrléans) #ONStorm" (Tweet) – via Twitter.
  45. ↑ "GTA, Southern Ontario feeling effects of severe thunder storm". Global News. Retrieved 24 May 2022.
  46. ↑ Bernstein, Jaela (25 May 2022). "What's a derecho and why is it so destructive? The science behind this powerful storm". CBC News. Retrieved 25 May 2022.
  47. ↑ "Hydro One". www.hydroone.com.
  48. 1 2 3 4 Lee, Joseph (23 May 2022). "Canada storms: Nearly a million homes lose power in high winds". BBC News. BBC. Retrieved 23 May 2022.
  49. ↑ "Canada storms: at least eight dead amid trail of destruction". The Guardian. Reuters. 22 May 2022. Retrieved 23 May 2022.
  50. ↑ https://www.accuweather.com/en/severe-weather/deadly-storm-canada-power/1191211
  51. ↑ @hydroottawa (May 26, 2022). "The storm damaged more than 300 poles across Ottawa. By comparison, 80 poles needed replacing after the 2018 tornad…" (Tweet) – via Twitter.
  52. ↑ "Hydro Ottawa says current outages significantly worse than ice storm, tornadoes". CBC News. CBC/Radio-Canada. 23 May 2022. Retrieved 23 May 2022.
  53. ↑ "Orages violents | la province victime d'un… derecho". La Presse. 24 May 2022.
  54. 1 2 Woolf, Marie (23 May 2022). "Death toll from Saturday's storm hits 10 across Ontario and Quebec". CTV News. Clarence-Rockland, Ontario: Bell Media. Retrieved 24 May 2022.
  55. ↑ Chung, Christine (22 May 2022). "At Least Six Dead After Severe Thunderstorms Lash Parts of Canada". The New York Times. Retrieved 23 May 2022.
  56. ↑ "Emergency alerts when severe weather happens can be improved: Guilbeault". 25 May 2022.
  57. ↑ "Weather summary for Ontario and the National Capital Region issued by Environment Canada at 11:35 p.m. EDT Sunday 22 May 2022". Government of Canada. Environment Canada. 22 May 2022. Archived from the original on 23 May 2022. Retrieved 23 May 2022.
  58. ↑ "More than 149,000 Quebec homes still without power after violent storm".
  59. ↑ ""It was crazy" – broker reacts to derecho and what lies ahead".
  60. 1 2 Bickis, Ian; Rabson, Mia (22 May 2022). "Cleanup underway after storm leaves at least nine dead, thousands without power". Toronto Star.
  61. ↑ Henson, Bob; Masters, Jeff (23 May 2022). "At least 11 dead in wake of Michigan tornado, Canada derecho". Yale Climate Connections. Retrieved 24 May 2022.
  62. 1 2 "Cleanup underway after storm leaves at least nine dead, thousands without power". The Toronto Star. 22 May 2022.
  63. ↑ "Storm damage 'simply beyond comprehension,' says Hydro Ottawa". CBC News. 2022-05-23. Archived from the original on 2023-03-19.
  64. ↑ "'This is unbelievable': Intense thunderstorm rolls through Ontario and Quebec, leaving five dead". Toronto Star. 21 May 2022.
  65. ↑ "Storm Response Update May 22, 2022". 23 May 2022.
  66. ↑ "Peterborough declares state of emergency, more than 150,000 still without power after massive storm". CBC News. CBC/Radio-Canada. 25 May 2022. Retrieved 26 May 2022.
  67. ↑ Jhalli, Anil (23 May 2022). "State of emergency not needed says Watson". CityNews Ottawa. Rogers Sports & Media. Retrieved 26 May 2022.
  68. 1 2 3 "Peterborough declares state of emergency, more than 150,000 still without power after massive storm". CBC News. 2022-05-25. Archived from the original on 2023-06-01.
  69. ↑ "'Bulk' of power system will be up and running Friday night, says Hydro Ottawa". CBC News. 2022-05-26. Archived from the original on 2022-11-11.
  70. ↑ "May 21 storm knocked out power for thousands". CBC News. 2022-06-02. Archived from the original on 2023-04-11.
  71. ↑ "Hydro One".
  72. ↑ "Some rural eastern Ontario residents could still be without power for weeks". CBC News. 2022-06-02. Archived from the original on 2023-04-16.
  73. 1 2 Marchesan, John; Morton, Michelle (22 May 2022). "Clean-up continues after Ontario storm leaves 10 dead, thousands without power". CityNews.
  74. ↑ "Challenging storm cleanup still far from over southwest of Ottawa". CBC News. 2022-06-06. Archived from the original on 2023-03-19.
  75. ↑ "A look at the outages caused by the May 21 derecho".
  76. ↑ Tunney, Joseph (26 May 2022). "Internet outages after storm frustrate residents in eastern Ontario". CBC News. Retrieved 26 May 2022.
  77. ↑ "Lovers of NCC woodlands, frustrated by storm cleanup, worry about Greenbelt's future".
  78. 1 2 3 4 "Ontario's chief election officer says storm or no storm, the vote goes on". Ottawa Citizen. June 2, 2022.
  79. ↑ "If voting's on your to-do list, here's how to check if the storm has closed your local voting site".
  80. ↑ "Two EF1 tornadoes in London, ON".
  81. ↑ "Elections Ontario working with hydro companies to restore power to polling stations".
  82. ↑ "Ways to Vote".
  83. 1 2 "What you need to know about storm cleanup and where to get help". CBC News. 22 May 2022.
  84. ↑ "Facebook". Facebook.
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