Hamilton, Ontario tornado of 2005
Encyclopedia
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
.
much further north than usual. On the morning of the November 9, a major autumn storm system
was passing through northern Ontario
(where heavy amounts of snow fell) with much milder air working in across the lower Great Lakes
. As the system began to occlude, southern Ontario was forecast to be in the triple point, a favourable area for the development of severe thunderstorms due to high helicity
values. Numerical models (especially the ETA model) had been predicting values of this, in excess of 600–800m^2/s^2 for the risk area.
Along the warm front
, some thunderstorm
s with rotation did develop towards the noon hour along the shores of Lake Erie
but this convection was highly elevated and no tornadoes were reported. Later in the afternoon around 3:20pm, as the cold front
approached from the west, a line of fast-moving thunderstorms developed rapidly in the Brantford
area. Gusty wind
s and very heavy downpours were reported by 3:45pm as they began to move into the west end of Hamilton.
, the area of worst damage was concentrated in the subdivisions just east of the Limeridge Shopping Centre. Berko Avenue was particularly hard hit, including Lawfield Elementary School. At that time the damage path was approximately 150 metres wide.
The school had the north part of its roof peeled off and the north wall had buckled underneath (this ultimately led to the school's demolition and relocation in following months). Large dumpsters in the school's parking lot were thrown 25 metres. Homes just across the street from Lawfield (on the north side of Berko Avenue) also sustained structural damage, with some of their roofs partially removed and trees snapped or uprooted (some of which were 2-3 feet in diameter). Just east of this area there was extensive damage to trees to Bobby Kerr Park but the tornado started to weaken (and probably lifted) shortly after this. There was some damage to a warehouse near the QEW on Millen Avenue but this damage was minor and intermittent by comparison.
On the following day, a storm survey team from Environment Canada toured the most heavily impacted portion of the track near Lawfield Elementary school and rated it as a strong F1 on the Fujita scale with winds of 118 to 180 km/h (73 to 112 mph) based on the aforementioned damage to trees and homes.
on December 12, 1946. The only other tornado this late in the season occurred near Leamington
on November 29, 1919.
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...
that touched down during the late afternoon hours of November 9, 2005 in the city of Hamilton, Ontario
Hamilton, Ontario
Hamilton is a port city in the Canadian province of Ontario. Conceived by George Hamilton when he purchased the Durand farm shortly after the War of 1812, Hamilton has become the centre of a densely populated and industrialized region at the west end of Lake Ontario known as the Golden Horseshoe...
.
Synoptic conditions
The first week of November that year had been unusually mild with the jet streamJet stream
Jet streams are fast flowing, narrow air currents found in the atmospheres of some planets, including Earth. The main jet streams are located near the tropopause, the transition between the troposphere and the stratosphere . The major jet streams on Earth are westerly winds...
much further north than usual. On the morning of the November 9, a major autumn storm system
Low pressure area
A low-pressure area, or "low", is a region where the atmospheric pressure at sea level is below that of surrounding locations. Low-pressure systems form under areas of wind divergence which occur in upper levels of the troposphere. The formation process of a low-pressure area is known as...
was passing through northern 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....
(where heavy amounts of snow fell) with much milder air working in across the lower Great Lakes
Great Lakes
The Great Lakes are a collection of freshwater lakes located in northeastern North America, on the Canada – United States border. Consisting of Lakes Superior, Michigan, Huron, Erie, and Ontario, they form the largest group of freshwater lakes on Earth by total surface, coming in second by volume...
. As the system began to occlude, southern Ontario was forecast to be in the triple point, a favourable area for the development of severe thunderstorms due to high helicity
Helicity (fluid mechanics)
In fluid mechanics, helicity is the extent to which helix-like motion occurs. If a parcel of fluid is moving, undergoing solid body motion rotating about an axis parallel to the direction of motion, it will have helicity...
values. Numerical models (especially the ETA model) had been predicting values of this, in excess of 600–800m^2/s^2 for the risk area.
Along the warm front
Warm front
A warm front is a density discontinuity located at the leading edge of a homogeneous warm air mass, and is typically located on the equator-facing edge of an isotherm gradient...
, some thunderstorm
Thunderstorm
A thunderstorm, also known as an electrical storm, a lightning storm, thundershower or simply a storm is a form of weather characterized by the presence of lightning and its acoustic effect on the Earth's atmosphere known as thunder. The meteorologically assigned cloud type associated with the...
s with rotation did develop towards the noon hour along the shores of Lake Erie
Lake Erie
Lake Erie is the fourth largest lake of the five Great Lakes in North America, and the tenth largest globally. It is the southernmost, shallowest, and smallest by volume of the Great Lakes and therefore also has the shortest average water residence time. It is bounded on the north by the...
but this convection was highly elevated and no tornadoes were reported. Later in the afternoon around 3:20pm, as the cold front
Cold front
A cold front is defined as the leading edge of a cooler mass of air, replacing a warmer mass of air.-Development of cold front:The cooler and denser air wedges under the less-dense warmer air, lifting it...
approached from the west, a line of fast-moving thunderstorms developed rapidly in the Brantford
Brantford, Ontario
Brantford is a city located on the Grand River in Southern Ontario, Canada. While geographically surrounded by the County of Brant, the city is politically independent...
area. Gusty wind
Wind
Wind is the flow of gases on a large scale. On Earth, wind consists of the bulk movement of air. In outer space, solar wind is the movement of gases or charged particles from the sun through space, while planetary wind is the outgassing of light chemical elements from a planet's atmosphere into space...
s and very heavy downpours were reported by 3:45pm as they began to move into the west end of Hamilton.
The tornado
By 4:00pm, as the thunderstorm was moving through the city of Hamilton, the tornado hit. Eyewitnesses reported seeing a funnel cloud overhead, laden with flying debris. While there were some hints of damage as far west as AncasterAncaster, Ontario
Ancaster is a picturesque and historic community located on the Niagara escarpment, within the greater area of the city of Hamilton, Ontario, Canada. This former town was founded officially in 1793 and was one of the oldest European communities established in present day Ontario along with Windsor...
, the area of worst damage was concentrated in the subdivisions just east of the Limeridge Shopping Centre. Berko Avenue was particularly hard hit, including Lawfield Elementary School. At that time the damage path was approximately 150 metres wide.
The school had the north part of its roof peeled off and the north wall had buckled underneath (this ultimately led to the school's demolition and relocation in following months). Large dumpsters in the school's parking lot were thrown 25 metres. Homes just across the street from Lawfield (on the north side of Berko Avenue) also sustained structural damage, with some of their roofs partially removed and trees snapped or uprooted (some of which were 2-3 feet in diameter). Just east of this area there was extensive damage to trees to Bobby Kerr Park but the tornado started to weaken (and probably lifted) shortly after this. There was some damage to a warehouse near the QEW on Millen Avenue but this damage was minor and intermittent by comparison.
On the following day, a storm survey team from Environment Canada toured the most heavily impacted portion of the track near Lawfield Elementary school and rated it as a strong F1 on the Fujita scale with winds of 118 to 180 km/h (73 to 112 mph) based on the aforementioned damage to trees and homes.
Climatological rarity
Southern Ontario usually receives about a dozen tornadoes each year, with most of them occurring between May and September. April and October tornadoes are much less common, and tornadoes rarely occur outside of those time frames. This November 9 tornado was the latest one recorded in Ontario since an F2 tornado hit near ExeterExeter, Ontario
Exeter is a Canadian community in the municipality of South Huron, in the southern portion of Huron County, Ontario, located approximately 50 kilometres north of London. The community proclaims itself the "Home of the White Squirrel", owing to the presence of the unusually-coloured mammals...
on December 12, 1946. The only other tornado this late in the season occurred near Leamington
Leamington, Ontario
Leamington is a municipality in Essex County, southern Ontario, Canada, and has a population of 31,113. It includes Point Pelee, the southernmost point of mainland Canada. It has a large H. J. Heinz Company factory and is known as the "Tomato Capital of Canada", with 4 km² of this crop in the...
on November 29, 1919.