A destructive, two-day tornado outbreak affected the Great Lakes region of the United States and the National Capital Region of Canada in late-September. A total of 37 tornadoes were confirmed, including a violent long-tracked high-end EF3 tornado that moved along a 80 km (50 mi) path from near Dunrobin, Ontario to Gatineau, Quebec, and an EF2 tornado in the Nepean sector of Ottawa. The tornadoes in Ottawa-Gatineau were declared one of the ten most significant weather events of 2018 in Canada by the Meteorological Service of Canada.[2]
Numerous tornadoes touched down in Minnesota on the initial day of the outbreak, including a high-end EF2 tornado that caused major damage in Morristown, Minnesota. Other damage occurred in Eastern Ontario due to downburst winds from the severe thunderstorms. One death was reported as a result of straight-line winds that occurred during the outbreak, and 31 people were injured.
Meteorological synopsis
In the Great Lakes region of the United States, a warm front surged in a hot, unstable air mass ahead of a strong cold front on September 20. An enhanced risk of severe weather was issued by the Storm Prediction Center (SPC), including a 10% hatched risk area for tornadoes stretching from southern Minnesota into Wisconsin.[3] Later that evening, a quasi-linear convective system with numerous embedded circulations and bowing line segments produced many tornadoes across southern Minnesota. This included a high-end EF2 tornado that heavily damaged or destroyed many homes in the town of Morristown, Minnesota. Another EF2 tornado damaged the local airport in Faribault. A few tornadoes were also confirmed in Iowa, Wisconsin, and Ohio, and damaging winds from the line of storms also caused significant damage. Embedded downbursts produced destructive straight-line winds of up to 100 mph (160 km/h) during the event. With 25 tornadoes in a matter of hours, this event was Minnesota's third most prolific tornado day on record.[4][5]
The severe weather threat was expected to move eastward to affect southern Ontario and a part of southwestern Quebec the next day.[6] On September 21, a significant severe weather threat was confirmed across southern Ontario and the Outaouais region of Quebec, with the potential for severe thunderstorms and tornadoes noted.[7]
Severe thunderstorm watches and warnings along with wind warnings and special weather statements were issued across parts of Ontario as early as the pre-dawn hours of September 21, which remained in effect until that evening. The warm humid air mass reached Ontario that morning of September 21, along with localized thunderstorms with heavy torrential downpours in most of the areas across southern Ontario and again later that day during the tornado outbreak. Record breaking temperatures across southern Ontario ranged from the high 20s into the low 30s.[8][9]
Tornado watches and warnings were issued by that afternoon.
Radar imagery at 2100 UTC (5 pm local) of a tornadic supercell thunderstorm approaching Gatineau, Quebec on September 21. Note the clearly visible hook echo.
On the afternoon of September 21, 2018, a localized outbreak of tornadoes impacted eastern Ontario and southern Quebec. During the event, Environment Canada issued numerous tornado warnings as multiple discrete tornadic supercells moved through the area.[10] Between 3:30 p.m. and 6:30 p.m. EDT, seven tornadoes, six of which were strong, caused severe damage in and around the National Capital Region of Canada.
The most significant tornado of the event made a direct strike on the small community of Dunrobin in the west end of Ottawa, then crossed the Ottawa River and struck the southern part of Luskville, the northern part of the Aylmer sector, and the Mont-Bleu residential area in the Hull sector before dissipating near the Pointe-Gatineau neighborhood of the Gatineau sector. The Dunrobin-Gatineau tornado was classified as a high-end, long-tracked EF3 tornado,[11] with peak winds reaching 265 km/h (165 mph).[12] Approximately 25 people were injured by the EF3 tornado, six of those taken to the hospital and five people had life-threatening injuries.[13] At least 200 buildings were damaged and an unknown number were destroyed along the path.[14][15] During the event, the long-tracked EF3 tornado that struck Dunrobin and Gatineau was visible on the horizon behind the Parliament Hill buildings in Ottawa.[16] A still image of the funnel was also captured from a live webcam.[17]
A second damaging tornado, rated EF2, caused significant damage in the Arlington Woods, Craig Henry, and Merivale Road residential areas of Nepean, with peak winds of 220 km/h (135 mph)[18] The tornadoes were preceded by severe thunderstorms throughout Ontario and Quebec.[19][20][21][22] Five other tornadoes also caused minor to moderate damage in the region, though they remained over remote forested areas and mostly damaged trees and power lines.[23][24][25]
The severe weather threat then diminished by late Friday evening, with cool windy conditions.[26]
Trees were damaged in town, and a garage was destroyed. A two-story office building at the Superior Ethanol plant sustained major roof damage, broken windows, and partial exterior wall failure on the second floor. A weather station at the plant measured a 99 mph (159 km/h) wind gust. Crops were damaged as well.[30][31]
This tornado touched down in Granada, where a house had its roof blown off, a small and unanchored home was shifted off its foundation and leveled, trees were downed, garages were destroyed, and other homes sustained roof damage. East of town, trees were snapped and sheet metal was strewn through fields.[32][33]
A weak tornado struck Garden City, downing trees at the fairgrounds. Outside of town, soybean fields were damaged and additional trees were downed.[34]
A house sustained roof loss and total destruction of its garage. The home owner was thrown from the garage into his yard, and sustained minor injuries. Outbuildings were damaged, a grain bin was thrown into a field. Other homes sustained minor damage, and trees were damaged as well.[36]
This tornado struck Waterville, where numerous trees were downed, many of which landed on homes. A one-story home had a large section of its roof torn off as well. Outside of town, tree limbs were snapped.[39][40]
This strong tornado touched down in the southeastern part of Morristown, and caused high-end EF2 damage as it impacted residential areas. Many trees were snapped and numerous homes were badly damaged, some of which lost roofs and exterior walls. One home was left with only a few walls standing. The tornado continued to the northeast outside of town, where a turkey barn and outbuildings were destroyed. Crops were damaged as well.[43]
Southwest of town, crops and trees were damaged and a barn was destroyed. In Owatonna, power poles and power lines were snapped, a large factory building sustained minor exterior damage, homes had shingles ripped off, and many trees were snapped or uprooted, some of which landed on homes.[45]
Significant damage occurred at the Faribault Airport, where several hangars were destroyed and roughly 80 airplanes were damaged or destroyed. The footings of one hangar were ripped from its frame. Hundreds of trees were downed, and outbuildings were damaged as well.[46]
Numerous trees were snapped or uprooted, some of which landed on homes and cabins. Outbuildings were destroyed, and one home sustained broken windows and considerable roof damage.[47]
Outbuildings, grain bins, machine sheds, and silos were damaged or destroyed along the path. Homes had portions of their roofs torn off, and many trees were snapped or uprooted.[48]
A pizza restaurant housed in a large barn was leveled by this high-end EF1 tornado. Other outbuildings were damaged or destroyed, and trees were damaged.[54][55]
This tornado touched down in Calabogie, snapping and uprooting many trees, causing roof damage to homes, and destroying a garage.[69][70][71][68] One person was injured.[68]
This destructive tornado touched down in Ontario near Kinburn, heavily damaging multiple homes, destroying barns and outbuildings, and mangling farm machinery. The tornado then struck Dunrobin at high-end EF3 strength, damaging or destroying numerous homes, a couple of which were leveled or swept from their foundations. Vehicles were thrown and destroyed, debris was scattered through fields, and a shopping plaza was severely damaged. The tornado maintained EF3 strength as it crossed into Quebec and moved through densely populated areas of Gatineau. Many apartment buildings sustained major structural damage in this area, many of which had their roofs torn off, with some sustaining collapse of their top floor exterior walls. Trees were snapped and debarked, several car dealerships were damaged, power poles were snapped, and cars were tossed and damaged as well. At least 200 buildings were damaged or destroyed, and 25 people were injured, five critically.[14][11][68]
Many trees were snapped and several buildings were damaged along the path. Homes sustained roof damage, and boats and docks were damaged as well.[67][68]
A tornado touched down and caused mainly tree damage near Sharbot Lake and to the north of St. George Lake. This event was initially classified as a downburst, until further analysis determined that it was a tornado.[72][68]
A rain-wrapped, high-end EF2 tornado touched down in western Nepean and struck the Arlington Woods and Craig Henry neighbourhoods, where many homes and apartment buildings were damaged. Some homes sustained roof loss, and a few sustained partial exterior wall failure as well. A church had much of its roof ripped off, and numerous large trees were snapped or uprooted, many of which landed on homes and vehicles. A metal truss tower was toppled over and mangled as well. Further east, a power substation was severely damaged, businesses had their roofs blown off, power poles were snapped, and a box truck was overturned. The Colonnade Road Business Park also sustained considerable damage. Additional trees and tree limbs were downed in the Greenboro neighbourhood before the tornado dissipated.[18][73][68]
High-resolution satellite imagery depicted tree damage through a forested area consistent with a tornado.[68]
Aftermath
Damage from the tornadoes caused more than 272,000 customers of the National Capital Region to lose power, with some of the outages lasting for days.[74][75][76] In addition to the tornadoes, microbursts and hail from the severe thunderstorms also caused considerable damage across Ontario and Quebec.[13][77][78][79]
Most of the severely damaged buildings that remained intact after the tornado were under repair. The Dunrobin Plaza shopping centre, which was severely damaged by the tornado, was demolished in December 2018, more than two months after the tornado.[80][81] In October 2018, a month after the storm, it was announced that the September 21 tornadoes caused a massive $295 million in insurance costs, making it one of 2018's costliest storms in Ontario.[82][83][84][85][86]
The Dunrobin-Gatineau EF3 tornado was the strongest to hit eastern Ontario since 1902.[87][88] The last time an EF3 tornado occurred in Ontario prior to this event was the Goderich tornado in August 2011. One non-tornadic death occurred as a result of this severe weather outbreak. The fatality was reported in the township of Rideau Lakes, Ontario, after a man was struck by a falling tree after being caught in straight-line winds.[89]
The National Capital Region power outages
One of the sites that was affected by the Arlington Woods EF2 tornado was the Merivale electrical substation, one of the two major stations in the city, located near the intersection of Merivale and Hunt Club Road in western Ottawa. While there is no proof confirming whether or not the tornado directly struck the station, it did rip off the roof of two nearby buildings, slamming into the infrastructure, insulators, and wires.[90]
Furthermore, the effects of the storm snapped approximately 80 to 90 Hydro poles in the area, downing many others, and leaving pole and wires dangling.[91]
This was the main reason for the longest power outages in the Ottawa-Gatineau region, affecting more than 300,000 customers of the 331,777 total customers who use Hydro Ottawa, plus those served on the Quebec side by Hydro-Québec.[92] Rebuilding the power plant was especially difficult, which took Hydro One and Hydro Ottawa two days working to repair enough of the damage to restore power. Finally, on the evening of September 22, power was restored in some neighbourhoods in southwestern Ottawa.[90] Repair of the downed poles was done as fast as possible, as to restore heat and power as well in several residences.
Although electricity had been restored, the power plant had still required additional repairs, and Hydro One continued working on critical repairs to the station in order to return it to its full potential state. Planned power outages around the city affected more than 50,000 Hydro One and Hydro Ottawa customers to replace important elements.[93] Work at the Merivale station was expected to last for several months.
^"Ohio Event Report: EF1 Tornado". National Centers for Environmental Information. National Weather Service Weather Forecast Office in Cleveland, Ohio. 2018. Retrieved March 14, 2019.
^"Ohio Event Report: EF1 Tornado". National Centers for Environmental Information. National Weather Service Weather Forecast Office in Cleveland, Ohio. 2018. Retrieved March 14, 2019.
^"Ohio Event Report: EF1 Tornado". National Centers for Environmental Information. National Weather Service Weather Forecast Office in Cleveland, Ohio. 2018. Retrieved March 14, 2019.
^"Iowa Event Report: EF1 Tornado". National Centers for Environmental Information. National Weather Service Weather Forecast Office in Sioux Falls, South Dakota. 2018. Retrieved March 14, 2019.
^"Iowa Event Report: EF0 Tornado". National Centers for Environmental Information. National Weather Service Weather Forecast Office in Des Moines, Iowa. 2018. Retrieved March 14, 2019.
^"Minnesota Event Report: EF1 Tornado". National Centers for Environmental Information. National Weather Service Weather Forecast Office Twin Cities, Minnesota. 2018. Retrieved March 14, 2019.
^"Minnesota Event Report: EF0 Tornado". National Centers for Environmental Information. National Weather Service Weather Forecast Office Twin Cities, Minnesota. 2018. Retrieved March 14, 2019.
^"Minnesota Event Report: EF0 Tornado". National Centers for Environmental Information. National Weather Service Weather Forecast Office Twin Cities, Minnesota. 2018. Retrieved March 14, 2019.
^"Minnesota Event Report: EF0 Tornado". National Centers for Environmental Information. National Weather Service Weather Forecast Office Twin Cities, Minnesota. 2018. Retrieved March 14, 2019.
^"Minnesota Event Report: EF1 Tornado". National Centers for Environmental Information. National Weather Service Weather Forecast Office Twin Cities, Minnesota. 2018. Retrieved March 14, 2019.
^"Minnesota Event Report: EF0 Tornado". National Centers for Environmental Information. National Weather Service Weather Forecast Office Twin Cities, Minnesota. 2018. Retrieved March 14, 2019.
^"Minnesota Event Report: EF1 Tornado". National Centers for Environmental Information. National Weather Service Weather Forecast Office Twin Cities, Minnesota. 2018. Retrieved March 14, 2019.
^"Minnesota Event Report: EF0 Tornado". National Centers for Environmental Information. National Weather Service Weather Forecast Office Twin Cities, Minnesota. 2018. Retrieved March 14, 2019.
^"Minnesota Event Report: EF0 Tornado". National Centers for Environmental Information. National Weather Service Weather Forecast Office Twin Cities, Minnesota. 2018. Retrieved March 14, 2019.
^"Minnesota Event Report: EF0 Tornado". National Centers for Environmental Information. National Weather Service Weather Forecast Office Twin Cities, Minnesota. 2018. Retrieved March 14, 2019.
^"Minnesota Event Report: EF0 Tornado". National Centers for Environmental Information. National Weather Service Weather Forecast Office Twin Cities, Minnesota. 2018. Retrieved March 14, 2019.
^"Minnesota Event Report: EF2 Tornado". National Centers for Environmental Information. National Weather Service Weather Forecast Office Twin Cities, Minnesota. 2018. Retrieved March 14, 2019.
^"Minnesota Event Report: EF1 Tornado". National Centers for Environmental Information. National Weather Service Weather Forecast Office Twin Cities, Minnesota. 2018. Retrieved March 14, 2019.
^"Minnesota Event Report: EF1 Tornado". National Centers for Environmental Information. National Weather Service Weather Forecast Office Twin Cities, Minnesota. 2018. Retrieved March 14, 2019.
^"Minnesota Event Report: EF2 Tornado". National Centers for Environmental Information. National Weather Service Weather Forecast Office Twin Cities, Minnesota. 2018. Retrieved March 14, 2019.
^"Minnesota Event Report: EF1 Tornado". National Centers for Environmental Information. National Weather Service Weather Forecast Office Twin Cities, Minnesota. 2018. Retrieved March 14, 2019.
^"Minnesota Event Report: EF1 Tornado". National Centers for Environmental Information. National Weather Service Weather Forecast Office Twin Cities, Minnesota. 2018. Retrieved March 14, 2019.
^"Minnesota Event Report: EF1 Tornado". National Centers for Environmental Information. National Weather Service Weather Forecast Office Twin Cities, Minnesota. 2018. Retrieved March 14, 2019.
^"Minnesota Event Report: EF1 Tornado". National Centers for Environmental Information. National Weather Service Weather Forecast Office Twin Cities, Minnesota. 2018. Retrieved March 14, 2019.
^"Minnesota Event Report: EF1 Tornado". National Centers for Environmental Information. National Weather Service Weather Forecast Office Twin Cities, Minnesota. 2018. Retrieved March 14, 2019.
^"Minnesota Event Report: EF1 Tornado". National Centers for Environmental Information. National Weather Service Weather Forecast Office Twin Cities, Minnesota. 2018. Retrieved March 14, 2019.
^"Minnesota Event Report: EF0 Tornado". National Centers for Environmental Information. National Weather Service Weather Forecast Office Twin Cities, Minnesota. 2018. Retrieved March 14, 2019.
^"Minnesota Event Report: EF1 Tornado". National Centers for Environmental Information. National Weather Service Weather Forecast Office Twin Cities, Minnesota. 2018. Retrieved March 14, 2019.
^"Minnesota Event Report: EF1 Tornado". National Centers for Environmental Information. National Weather Service Weather Forecast Office Twin Cities, Minnesota. 2018. Retrieved March 14, 2019.
^"Minnesota Event Report: EF0 Tornado". National Centers for Environmental Information. National Weather Service Weather Forecast Office Twin Cities, Minnesota. 2018. Retrieved March 14, 2019.
^"Minnesota Event Report: EF1 Tornado". National Centers for Environmental Information. National Weather Service Weather Forecast Office Twin Cities, Minnesota. 2018. Retrieved March 14, 2019.
^"Minnesota Event Report: EF0 Tornado". National Centers for Environmental Information. National Weather Service Weather Forecast Office Twin Cities, Minnesota. 2018. Retrieved March 14, 2019.
^"Minnesota Event Report: EF0 Tornado". National Centers for Environmental Information. National Weather Service Weather Forecast Office Twin Cities, Minnesota. 2018. Retrieved March 14, 2019.
^"Minnesota Event Report: EF0 Tornado". National Centers for Environmental Information. National Weather Service Weather Forecast Office Twin Cities, Minnesota. 2018. Retrieved March 14, 2019.
^"Minnesota Event Report: EF0 Tornado". National Centers for Environmental Information. National Weather Service Weather Forecast Office Twin Cities, Minnesota. 2018. Retrieved March 14, 2019.
^"Minnesota Event Report: EF0 Tornado". National Centers for Environmental Information. National Weather Service Weather Forecast Office Twin Cities, Minnesota. 2018. Retrieved March 14, 2019.
^"Minnesota Event Report: EF0 Tornado". National Centers for Environmental Information. National Weather Service Weather Forecast Office Twin Cities, Minnesota. 2018. Retrieved March 14, 2019.
^"Minnesota Event Report: EF0 Tornado". National Centers for Environmental Information. National Weather Service Weather Forecast Office Twin Cities, Minnesota. 2018. Retrieved March 14, 2019.
^"Wisconsin Event Report: EF0 Tornado". National Centers for Environmental Information. National Weather Service Weather Forecast Office Twin Cities, Minnesota. 2018. Retrieved March 14, 2019.
^"Wisconsin Event Report: EF0 Tornado". National Centers for Environmental Information. National Weather Service Weather Forecast Office Twin Cities, Minnesota. 2018. Retrieved March 14, 2019.
