Southern Ontario Tornado Outbreak of 2009
Encyclopedia
The Southern Ontario Tornado Outbreak of 2009 was a series of severe thunderstorms that spawned numerous tornadoes in Southwestern Ontario
, Central Ontario and the Greater Toronto Area
(GTA
) on August 20, 2009, and was the largest single-day tornado
outbreak in Ontario history and the largest in Canadian history. During the afternoon and evening, nineteen tornadoes touched down with four of them producing F2 damage. One F2 struck the town of Durham where significant damage occurred and one person was killed; two F2s struck the city of Vaughan, just north of Toronto, damaging hundreds of homes; another F2 devastated apple orchards and resort areas near Thornbury. The number of tornadoes associated with this event surpasses that of August 2, 2006, which saw 18 documented tornadoes. In addition, it was one of the most destructive and costly tornado events ever in the province, and included one fatality, one of only a handful of deadly tornadoes in Ontario's recent memory. At one point, over 10 million people in Southern Ontario, one-third of Canada's population, were placed under Tornado Watches
and/or Warnings
as the storms rolled through.
, increasing in number as they moved into western sections of Southwestern Ontario
. Beginning at around 3:00pm, the storms rapidly strengthened, with a particularly intense cell forming to the south of Lake Huron
. This storm passed into Ontario
, travelled to the northeast through Huron County
and into Grey County
, moving towards the town of Durham
. The first tornado touchdown occurred about 14 km southwest of the town, and the tornado grew in size and intensity as it approached, reaching F2 status as it inflicted severe damage to homes and industrial park in the southwest part of the town.
The tornado weakened and continued through more rural areas before striking the town of Markdale
, where F0 damage occurred to homes and trees. The total path of this tornado was 36 km long, making it the longest track tornado in Ontario since the Williamsford and Arthur tornadoes of 1996.
The next significant tornado to touch down occurred near the town of Thornbury along the shore of Georgian Bay
. The tornado developed to the south of there, passing through Clarksburg and Blue Mountain, before moving out over the water. It was later rated at F2. As this cell moved out over Georgian Bay
, more cells formed and intensified ahead of and within the main line as it moved eastward.
One supercell developed to the southwest of Barrie
, and produced a family of four tornadoes as it tracked to the northeast for 125 kilometers. The first touched down west of Barrie
, staying on the ground for 12.6 km. This tornado hit rural areas between New Lowell and Edenvale
. The second tornado touched down near Moonstone, while the third cut a 1 km wide, 10 km long path through the town of Gravenhurst
, both of them an F0. The final tornado of this family, an F1, touched at Ril Lake. To the north of there, an caused F0 tornado affected Dollars Lake, to the northeast of Britt
, while another F1 tornado hit at Arnstein near North Bay
. To the east, F0 damage occurred from a tornado at Redstone Lake near Haliburton, where a woman was injured by flying glass and the roofs of cottages were damaged. Nearby in Haliburton County
, another tornado inflicted F1 damage to trees at Haliburton Forest.
To the south, the most prolific tornadoes in the Greater Toronto Area
in recent memory tore through sections to the north and east of Toronto. An isolated cell produced a tornado that swept across the Royal Riding Academy in rural Newmarket
. To this storm's west, another tornadic cell developed and ultimately produced the most damaging tornadoes in an urban area of Ontario since The "Barrie" Tornado Outbreak of 1985. Although originally thought to be a single tornado, two separate F2 tornadoes struck the city of Vaughan
. The first hit the Woodbridge neighbourhood in the city's southwest, traveling for 3.5 km. The second struck the Maple neighbourhood in the city's northeast, causing a 2.7 km path of damage. Both of these tornadoes have been rated F2.
Following the Vaughan
tornadoes, the storms moved into sections of Central Ontario and Eastern Ontario
. There, an F0 tornado struck near Orono, an F1 touched down in the Bancroft/Carlow Mayo area, and a final confirmed F1 tornado at Rice Lake.
, causing serious structural damage to several businesses in the town's small industrial park, including the complete destruction of a press plant. Damage to homes and businesses in this area was rated at F2. Passing through and to the northeast of town, the tornado then hit a conservation area where a children's day camp was taking place. The tornado hurled debris from a gatehouse and other buildings and trees onto a tent structure where the children and counselors were seeking shelter. One eleven-year-old boy was killed by flying debris, while several other children suffered serious, but non life-threatening injuries.
tornadoes weakened over the lake, having travelled and sustained its intensity for, according to Environment Canada
, "a remarkable 200km."
. The final tornado of this family caused F1 damage to trees and cottages at Ril Lake. To the north of there, the Dollars Lake F0 caused tree damage..
, the tornado damaged buildings and flipped over cars and vehicles. Hundreds of people had been at the Royal Riding Academy attending a riding show, but saw the tornado well in advance and either left the facility or sought shelter before the tornado struck. Damage here was rated at F1, and casualties may have been higher had the tornado been stronger; many sought shelter in weak structures such as barns, sheds and horse trailers, including teenagers who were uninjured after the horse trailer they were in was tossed on its side.
tornadoes hit the Woodbridge neighbourhood in the city's southwest, flipping cars, damaging dozens of homes - many severely - as well as numerous businesses and a school. The second struck the Maple neighbourhood in the city's northeast, causing a 2.7 km path of damage to dozens of homes. Over six hundred homes in the city were damaged by the tornadoes, with over forty of them being deemed uninhabitable immediately after the event; a handful of these homes ultimately had to be torn down and rebuilt. Although both of these tornadoes have been rated F2, a researcher from the University of Western Ontario who studied the damage concluded that some of the destruction from one of the Vaughan tornadoes may be indicative of a lower-end F3 tornado.
was declared in the city of Vaughan
and in West Grey
, including the town of Durham
. In addition, two days after the tornado that affected the Blue Mountain area, a State of Emergency was declared there.
Damage from the tornadoes in Grey County
alone is conservatively estimated at over 30 million dollars. With damage at Vaughan estimated to be well over ten million dollars, the cost of this event surpasses that of the 1996 Southern Ontario tornadoes which caused insured losses of eight million dollars, and the Hamilton, Ontario tornado of 2005
which caused twenty five million dollars in damage at Lawfield Public School. As such, the outbreak is the costliest in Ontario since 1985 directly related to Tornado Damage.
Given their intensity and urban setting, particularly the tornadoes at Vaughan, the outbreak garnered media attention unlike any other in recent years. Cable news network CP24 set a viewing record with over 1.2 million tuning in. The public interest in the tornadoes was mirrored by that of politicians; a review of the tornado warning process and changes to the dissemination of severe weather warnings in Canada will be made accordingly.
Southwestern Ontario
Southwestern Ontario is a subregion of Southern Ontario in the Canadian province of Ontario, centred on the city of London. It extends north to south from the Bruce Peninsula on Lake Huron to the Lake Erie shoreline, and east to south-west roughly from Guelph to Windsor. The region had a population...
, Central Ontario and the Greater Toronto Area
Greater Toronto Area
The Greater Toronto Area is the largest metropolitan area in Canada, with a 2006 census population of 5.5 million. The Greater Toronto Area is usually defined as the central city of Toronto, along with four regional municipalities surrounding it: Durham, Halton, Peel, and York...
(GTA
GTA
- Events :*Golden Tap Awards, an annual beer awards event held in Toronto, Ontario, Canada*Golden Ticket Awards, the most prestigious awards in the amusement industry- Media :*Grand Theft Auto , a 1977 film directed by Ron Howard...
) on August 20, 2009, and was the largest single-day tornado
Tornado
A tornado is a violent, dangerous, rotating column of air that is in contact with both the surface of the earth and a cumulonimbus cloud or, in rare cases, the base of a cumulus cloud. They are often referred to as a twister or a cyclone, although the word cyclone is used in meteorology in a wider...
outbreak in Ontario history and the largest in Canadian history. During the afternoon and evening, nineteen tornadoes touched down with four of them producing F2 damage. One F2 struck the town of Durham where significant damage occurred and one person was killed; two F2s struck the city of Vaughan, just north of Toronto, damaging hundreds of homes; another F2 devastated apple orchards and resort areas near Thornbury. The number of tornadoes associated with this event surpasses that of August 2, 2006, which saw 18 documented tornadoes. In addition, it was one of the most destructive and costly tornado events ever in the province, and included one fatality, one of only a handful of deadly tornadoes in Ontario's recent memory. At one point, over 10 million people in Southern Ontario, one-third of Canada's population, were placed under Tornado Watches
Tornado watch
A tornado watch is issued when conditions are right for a tornado to form. Since any thunderstorm capable of producing a tornado is defined as severe, a tornado watch is also automatically a severe thunderstorm watch...
and/or Warnings
Tornado warning
A tornado warning is an alert issued by government weather services to warn that severe thunderstorms with tornadoes may be imminent. It can be issued after a tornado or funnel cloud has been spotted by eye, or more commonly if there are radar indications of tornado formation...
as the storms rolled through.
Meteorological events
During the afternoon of August 20, 2009, a series of supercell thunderstorms began to develop over southeast MichiganMichigan
Michigan is a U.S. state located in the Great Lakes Region of the United States of America. The name Michigan is the French form of the Ojibwa word mishigamaa, meaning "large water" or "large lake"....
, increasing in number as they moved into western sections of Southwestern Ontario
Southwestern Ontario
Southwestern Ontario is a subregion of Southern Ontario in the Canadian province of Ontario, centred on the city of London. It extends north to south from the Bruce Peninsula on Lake Huron to the Lake Erie shoreline, and east to south-west roughly from Guelph to Windsor. The region had a population...
. Beginning at around 3:00pm, the storms rapidly strengthened, with a particularly intense cell forming to the south of Lake Huron
Lake Huron
Lake Huron is one of the five Great Lakes of North America. Hydrologically, it comprises the larger portion of Lake Michigan-Huron. It is bounded on the east by the Canadian province of Ontario and on the west by the state of Michigan in the United States...
. This storm passed into Ontario
Ontario
Ontario is a province of Canada, located in east-central Canada. It is Canada's most populous province and second largest in total area. It is home to the nation's most populous city, Toronto, and the nation's capital, Ottawa....
, travelled to the northeast through Huron County
Huron County, Ontario
Huron County is a census division and county of the province of Ontario, Canada. It is located on the southeast shore of its namesake, Lake Huron, in the southwest part of the province...
and into Grey County
Grey County, Ontario
Grey County is a county and census division of the Canadian province of Ontario. The county seat is in Owen Sound. The population was 92,411 in 2006. It is located in the subregion of Southern Ontario named Southwestern Ontario...
, moving towards the town of Durham
Durham, Ontario
Durham is a community in the municipality of West Grey, Grey County, Ontario, Canada. Durham is located near the base of the Bruce Peninsula.-Location:...
. The first tornado touchdown occurred about 14 km southwest of the town, and the tornado grew in size and intensity as it approached, reaching F2 status as it inflicted severe damage to homes and industrial park in the southwest part of the town.
The tornado weakened and continued through more rural areas before striking the town of Markdale
Markdale, Ontario
Markdale is a community in the Municipality of Grey Highlands, in Grey County, Ontario, Canada.Markdale was first settled in 1846 and originally called East Glenelg, after a nearby township. In 1864, it was renamed Cornabus after the Islay, Scotland hometown of then-postmaster Donald MacDuffie...
, where F0 damage occurred to homes and trees. The total path of this tornado was 36 km long, making it the longest track tornado in Ontario since the Williamsford and Arthur tornadoes of 1996.
The next significant tornado to touch down occurred near the town of Thornbury along the shore of Georgian Bay
Georgian Bay
Georgian Bay is a large bay of Lake Huron, located entirely within Ontario, Canada...
. The tornado developed to the south of there, passing through Clarksburg and Blue Mountain, before moving out over the water. It was later rated at F2. As this cell moved out over Georgian Bay
Georgian Bay
Georgian Bay is a large bay of Lake Huron, located entirely within Ontario, Canada...
, more cells formed and intensified ahead of and within the main line as it moved eastward.
One supercell developed to the southwest of Barrie
Barrie, Ontario
Barrie is a city in Southern Ontario, Canada, located on the western shore of Lake Simcoe, approximately 90 km north of Toronto. Although located in Simcoe County, the city is politically independent...
, and produced a family of four tornadoes as it tracked to the northeast for 125 kilometers. The first touched down west of Barrie
Barrie, Ontario
Barrie is a city in Southern Ontario, Canada, located on the western shore of Lake Simcoe, approximately 90 km north of Toronto. Although located in Simcoe County, the city is politically independent...
, staying on the ground for 12.6 km. This tornado hit rural areas between New Lowell and Edenvale
Edenvale, Ontario
The former Village of Edenvale is a ghost town in the Province of Ontario, Canada. It was located on Ontario Highway 26 in Springwater Township, along the Nottawasaga River, in Simcoe County...
. The second tornado touched down near Moonstone, while the third cut a 1 km wide, 10 km long path through the town of Gravenhurst
Gravenhurst, Ontario
Gravenhurst is a town in the Muskoka Region of Ontario, Canada. It is located approximately south of Bracebridge, Ontario. The mayor is Paisley Donaldson...
, both of them an F0. The final tornado of this family, an F1, touched at Ril Lake. To the north of there, an caused F0 tornado affected Dollars Lake, to the northeast of Britt
Britt, Ontario
Britt is a community in the Canadian province of Ontario, located in the unincorporated township of Wallbridge in the Parry Sound District.The community is located on the north shore of the Magnetawan River at Byng Inlet, approximately 5 kilometres west of Highway 69, at the end of Highway 526.Like...
, while another F1 tornado hit at Arnstein near North Bay
North Bay, Ontario
North Bay is a city in Northeastern Ontario, Canada. It is the seat of Nipissing District, and takes its name from its position on the shore of Lake Nipissing.-History:...
. To the east, F0 damage occurred from a tornado at Redstone Lake near Haliburton, where a woman was injured by flying glass and the roofs of cottages were damaged. Nearby in Haliburton County
Haliburton County, Ontario
Haliburton is a county of Ontario, Canada, known as a tourist and cottage area in Central Ontario for its scenery and for its resident artists. Minden Hills is the county seat. Haliburton County was established in 1983, but had existed as the Provisional County of Haliburton since 1874...
, another tornado inflicted F1 damage to trees at Haliburton Forest.
To the south, the most prolific tornadoes in the Greater Toronto Area
Greater Toronto Area
The Greater Toronto Area is the largest metropolitan area in Canada, with a 2006 census population of 5.5 million. The Greater Toronto Area is usually defined as the central city of Toronto, along with four regional municipalities surrounding it: Durham, Halton, Peel, and York...
in recent memory tore through sections to the north and east of Toronto. An isolated cell produced a tornado that swept across the Royal Riding Academy in rural Newmarket
Newmarket, Ontario
Newmarket is a town in Southern Ontario located approximately 50 km north of downtown Toronto, Ontario, Canada. It is part of the Greater Toronto Area and is connected to Toronto by freeway, and is served by three interchanges along Highway 404. It is also connected to Highway 400 via Highway 9...
. To this storm's west, another tornadic cell developed and ultimately produced the most damaging tornadoes in an urban area of Ontario since The "Barrie" Tornado Outbreak of 1985. Although originally thought to be a single tornado, two separate F2 tornadoes struck the city of Vaughan
Vaughan, Ontario
Vaughan is a city in York Region north of Toronto, Ontario, Canada. Vaughan is the fastest growing municipality in Canada achieving a population growth rate of 80.2% between 1996–2006, according to Statistics Canada having nearly doubled in population since 1991. Vaughan is located in Southern...
. The first hit the Woodbridge neighbourhood in the city's southwest, traveling for 3.5 km. The second struck the Maple neighbourhood in the city's northeast, causing a 2.7 km path of damage. Both of these tornadoes have been rated F2.
Following the Vaughan
Vaughan, Ontario
Vaughan is a city in York Region north of Toronto, Ontario, Canada. Vaughan is the fastest growing municipality in Canada achieving a population growth rate of 80.2% between 1996–2006, according to Statistics Canada having nearly doubled in population since 1991. Vaughan is located in Southern...
tornadoes, the storms moved into sections of Central Ontario and Eastern Ontario
Eastern Ontario
Eastern Ontario is a subregion of Southern Ontario in the Canadian province of Ontario which lies in a wedge-shaped area between the Ottawa River and St. Lawrence River...
. There, an F0 tornado struck near Orono, an F1 touched down in the Bancroft/Carlow Mayo area, and a final confirmed F1 tornado at Rice Lake.
Impacts
Durham tornado
The first tornado was at its most powerful as it passed through the southeast section of DurhamDurham, Ontario
Durham is a community in the municipality of West Grey, Grey County, Ontario, Canada. Durham is located near the base of the Bruce Peninsula.-Location:...
, causing serious structural damage to several businesses in the town's small industrial park, including the complete destruction of a press plant. Damage to homes and businesses in this area was rated at F2. Passing through and to the northeast of town, the tornado then hit a conservation area where a children's day camp was taking place. The tornado hurled debris from a gatehouse and other buildings and trees onto a tent structure where the children and counselors were seeking shelter. One eleven-year-old boy was killed by flying debris, while several other children suffered serious, but non life-threatening injuries.
Thornbury and Clarksburg tornadoes
The Thornbury and Clarksburg F2 tornado produced serious damage to homes and chalets in this popular ski resort area. At the resort itself, Georgian Peaks, the tornado tore the roof from the Alpine Centre, pulled cables from chair lifts and ripped apart lift houses and ski ramps. Although damage to homes and the resort was extensive, perhaps the greatest economic toll was to the owners of local apple orchards which were severely affected. The tornadic storm responsible for the Grey CountyGrey County, Ontario
Grey County is a county and census division of the Canadian province of Ontario. The county seat is in Owen Sound. The population was 92,411 in 2006. It is located in the subregion of Southern Ontario named Southwestern Ontario...
tornadoes weakened over the lake, having travelled and sustained its intensity for, according to Environment Canada
Environment Canada
Environment Canada , legally incorporated as the Department of the Environment under the Department of the Environment Act Environment Canada (EC) (French: Environnement Canada), legally incorporated as the Department of the Environment under the Department of the Environment Act Environment...
, "a remarkable 200km."
Barrie tornado
In the Barrie area, two farm homes were partially unroofed, a shed collapsed and a heavy trailer was picked and moved a distance of over 100 m with the Edenvale tornado. The second tornado caused F0 damage to cottages, homes and trees at Moonstone. The third produced F0 damage to trees and homes GravenhurstGravenhurst, Ontario
Gravenhurst is a town in the Muskoka Region of Ontario, Canada. It is located approximately south of Bracebridge, Ontario. The mayor is Paisley Donaldson...
. The final tornado of this family caused F1 damage to trees and cottages at Ril Lake. To the north of there, the Dollars Lake F0 caused tree damage..
Newmarket tornado
In NewmarketNewmarket, Ontario
Newmarket is a town in Southern Ontario located approximately 50 km north of downtown Toronto, Ontario, Canada. It is part of the Greater Toronto Area and is connected to Toronto by freeway, and is served by three interchanges along Highway 404. It is also connected to Highway 400 via Highway 9...
, the tornado damaged buildings and flipped over cars and vehicles. Hundreds of people had been at the Royal Riding Academy attending a riding show, but saw the tornado well in advance and either left the facility or sought shelter before the tornado struck. Damage here was rated at F1, and casualties may have been higher had the tornado been stronger; many sought shelter in weak structures such as barns, sheds and horse trailers, including teenagers who were uninjured after the horse trailer they were in was tossed on its side.
Vaughan tornadoes
The first of the VaughanVaughan, Ontario
Vaughan is a city in York Region north of Toronto, Ontario, Canada. Vaughan is the fastest growing municipality in Canada achieving a population growth rate of 80.2% between 1996–2006, according to Statistics Canada having nearly doubled in population since 1991. Vaughan is located in Southern...
tornadoes hit the Woodbridge neighbourhood in the city's southwest, flipping cars, damaging dozens of homes - many severely - as well as numerous businesses and a school. The second struck the Maple neighbourhood in the city's northeast, causing a 2.7 km path of damage to dozens of homes. Over six hundred homes in the city were damaged by the tornadoes, with over forty of them being deemed uninhabitable immediately after the event; a handful of these homes ultimately had to be torn down and rebuilt. Although both of these tornadoes have been rated F2, a researcher from the University of Western Ontario who studied the damage concluded that some of the destruction from one of the Vaughan tornadoes may be indicative of a lower-end F3 tornado.
Eastern Ontario tornadoes
Further east, the F0 produced only the minor home and tree damage near Orono, in Bancroft/Carlow Mayo area the produced F1 caused damage to trees and hunting cabins, and a final confirmed tornado, an F1, caused roof and tree damage at Rice Lake.Aftermath
In the hours after the tornadoes touched down, a state of emergencyState of emergency
A state of emergency is a governmental declaration that may suspend some normal functions of the executive, legislative and judicial powers, alert citizens to change their normal behaviours, or order government agencies to implement emergency preparedness plans. It can also be used as a rationale...
was declared in the city of Vaughan
Vaughan, Ontario
Vaughan is a city in York Region north of Toronto, Ontario, Canada. Vaughan is the fastest growing municipality in Canada achieving a population growth rate of 80.2% between 1996–2006, according to Statistics Canada having nearly doubled in population since 1991. Vaughan is located in Southern...
and in West Grey
West Grey, Ontario
West Grey is a township in western Ontario, Canada, in Grey County spanning across the River Styx, the Rocky Saugeen River, the Beatty Saugeen River, and the South Saugeen River...
, including the town of Durham
Durham, Ontario
Durham is a community in the municipality of West Grey, Grey County, Ontario, Canada. Durham is located near the base of the Bruce Peninsula.-Location:...
. In addition, two days after the tornado that affected the Blue Mountain area, a State of Emergency was declared there.
Damage from the tornadoes in Grey County
Grey County, Ontario
Grey County is a county and census division of the Canadian province of Ontario. The county seat is in Owen Sound. The population was 92,411 in 2006. It is located in the subregion of Southern Ontario named Southwestern Ontario...
alone is conservatively estimated at over 30 million dollars. With damage at Vaughan estimated to be well over ten million dollars, the cost of this event surpasses that of the 1996 Southern Ontario tornadoes which caused insured losses of eight million dollars, and the Hamilton, Ontario tornado of 2005
Hamilton, Ontario tornado of 2005
The Hamilton, Ontario tornado of 2005 was a tornado that touched down during the late afternoon hours of November 9, 2005 in the city of Hamilton, Ontario.-Synoptic conditions:...
which caused twenty five million dollars in damage at Lawfield Public School. As such, the outbreak is the costliest in Ontario since 1985 directly related to Tornado Damage.
Given their intensity and urban setting, particularly the tornadoes at Vaughan, the outbreak garnered media attention unlike any other in recent years. Cable news network CP24 set a viewing record with over 1.2 million tuning in. The public interest in the tornadoes was mirrored by that of politicians; a review of the tornado warning process and changes to the dissemination of severe weather warnings in Canada will be made accordingly.
See also
- Heat wave of 2006 derecho series, record-setting number of tornadoes in one outbreak sequence that touched down in Southern Ontario, until the 2009 Southern Ontario tornado outbreak.
- Southern Ontario Tornado Outbreak of 2005Southern Ontario Tornado Outbreak of 2005The Southern Ontario Tornado Outbreak of 2005 in a series of thunderstorms on the afternoon of August 19, 2005, spawned tornadoes damaging homes in the Conestoga Lake, Fergus, and Tavistock areas. A tornado was reported within the Toronto city limits, although this was never officially confirmed by...
, among the highest recorded storm-related insurance claims in Canada, mostly because of record rainfall in the Toronto area from a dying tornadic supercell. - The "Barrie" Tornado Outbreak of 1985, the deadly and violent tornado outbreak that occurred in Southern Ontario.