Environment Canada

Environment Canada

August 02, 2005 11:30 ET

Environment Canada: Ontario Weather Review

TORONTO, ONTARIO--(CCNMatthews - Aug. 2, 2005) -

July 2005

The heat goes on...with June's hot weather continuing into July. Temperatures in mid-month reached 30 degrees C in many areas and stayed there for days. Air conditioners were put to the test as hot, humid, hazy, weather remained in place for long periods of time. Maximum record temperatures were broken daily throughout the province. Overall temperatures for the month ranged from one to 3.5 degrees above normal.

Along with the heat, dry conditions were reported in many areas, with some locations receiving less than 15% of their normal monthly rainfall. A few areas haven't had a July as dry as 2005 since the 1940s. However, there were still locations that received normal or above-normal amounts of precipitation due to the passage of heavy showers and thunderstorms.

Severe Weather

The long stretches of very warm and humid air that occurred over much of the province this month acted as the fuel that contributed to the formation of a number of severe thunderstorms. During the course of the month, a variety of locations in Southern Ontario experienced brief bursts of damaging wind gusts from severe thunderstorms. These wind gusts were occasionally on the order of 100 kilometres per hour or more and caused damage to trees and hydro lines.

In addition, heavy rains sparked by the remnants of hurricane Dennis caused local flooding in the Kitchener area on July 16, when more than 100 millimetres of rain fell during that day. Another band of thunderstorms caused local flooding in the Paris and Hamilton areas on July 26.

However, the largest and most damaging thunderstorms in July were reserved for Northwestern Ontario. Two large thunderstorm complexes moved through areas to the northwest and north of Red Lake during the month. On July 10 in the Sabourin Lake area, 70 kilometres northwest of Red Lake, a large thunderstorm moved through with associated wind gusts in excess of 100 kilometres per hour and caused a fair amount of tree damage. The situation was repeated on July 17 when another massive thunderstorm complex moved through the Bak Lake and Zeller Lake area, 80 kilometres north of Red Lake, leaving a trail of destruction approximately 45 kilometres long and five to eight kilometres wide.

Thanks to a number of aerial photos and maps provided by the Ontario Ministry of Natural Resources, Aviation and Forest Fire Management Branch, Environment Canada was able to determine that part of the damage caused in the Bak Lake and Zeller Lake areas on July 17 was due to a probable Fujita Scale 1 tornado. Fujita Scale 1 tornadoes have winds between 120 and 180 km/h. With the inclusion of this tornado, the summer 2005 Ontario tornado total now stands at seven.

Given the two significant events this past month in the Red Lake area and other damaging storms that occurred in the Dryden and Atikokan areas in June, it is important to reinforce the fact that severe thunderstorms and tornadoes can occur anywhere in the province.



Unusual high temperature readings:

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Location Mean Temp. Normal Difference Warmest Since
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Toronto Pearson 24.1 20.8 +3.3 1999
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Trenton 22.9 20.5 +2.4 1955
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Moosonee 17.8 15.4 +2.4 1959
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Kapuskasing 19.5 17.2 +2.3 1955
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North Bay 20.9 18.6 +2.3 1955
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Wawa 18.0 15.8 +2.2 1983
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Kingston 23.6 21.4 +2.2 1999
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Toronto City 24.3 22.2 +2.1 2002
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Unusual low precipitation readings (in millimetres):

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Location Precip. Normal Difference Driest since
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Wawa 13.6 101.5 -87.9 1989
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Geraldton 46.2 111.7 -65.5 1989
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Kapuskasing 35.7 100.5 -64.8 1940
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North Bay 42.4 100.1 -57.7 2001
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Toronto Pearson 20.4 74.4 -54.0 1983
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Dryden 49.0 98.8 -49.8 2002
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Chapleau 50.2 86.7 -36.5 2001
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Timmins 55.6 91.5 -35.9 2002
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Thunder Bay 57.0 89.0 -32.0 2002
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Moosonee 72.0 101.3 -29.3 2004
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Petawawa 50.0 76.5 -26.5 1993
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Sault Ste Marie 50.2 76.8 -26.4 2001
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Earlton 54.0 79.7 -25.7 2001
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Unusual high precipitation readings (in millimetres):

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Location Precip. Normal Difference Wettest since
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Waterloo Wellington 190.5 91.8 +98.7 1988
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Kingston 95.4 59.8 +35.6 2004
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Sioux Lookout 120.8 85.3 +35.5 2001
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Elliot Lake 107.8 79.0 +28.8 2004
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Contact Information

  • Environment Canada, Ontario Region
    Jack Saunders
    Communications Advisor/Media Relations
    (416) 739-4785
    (Egalement offert en francais)
    www.ec.gc.ca