Elie tornado upgraded to highest level on damage scale - Canada's first official F5 tornado



    WINNIPEG, Sept. 18 /CNW Telbec/ - Environment Canada meteorologists have
confirmed that the Elie, Manitoba tornado of June 22, 2007 reached F5
intensity, the highest rating on the Fujita tornado damage scale, making it
the first officially documented F5 tornado in Canada.
    The Fujita scale measures the strength of tornadoes based on damage
indicators. An F5 tornado accounts for about one tenth of one percent of all
tornadoes in North America.
    Preliminary assessment by Environment Canada's onsite storm survey team
had earlier indicated clear evidence of F4 damage. However, damage seen at two
of the homes indicated possible F5 intensity. Based on further evaluation,
including review of additional video images, Environment Canada meteorologists
at the Prairie and Arctic Storm Prediction Centre in Winnipeg confirm evidence
of F5 level damage.
    Environment Canada reports the video confirmed some of the suspected F5
evidence seen onsite in June. An almost intact house can be seen being thrown
several hundred metres through the air before disintegrating and falling to
the ground. Seconds later a heavy van is seen being whirled through the air;
it was later found in an open field south of the main damage.
    In order to rate a tornado, only one instance of any one damage indicator
has to be clearly met. With two F5 damage indicators occurring within seconds
of each other, experts decided to re-evaluate some of the evidence seen in
June.
    The Elie tornado was on the ground for about 35 minutes, and traveled for
a distance of about 5.5 km. Damage occurred in a swath up to 300 metres wide.
Wind speeds are estimated to have reached between 420 to 510 km/h when the
tornado was at its most intense.
    Fortunately, there were no fatalities or serious injuries with either the
Elie tornado or the F4 tornado which struck Birtle, Manitoba in 1994.
Manitoba's only other documented F4 tornado, which struck the Rosa-St. Malo
area in 1977, resulted in three fatalities. The F2 tornado which struck Gull
Lake, Manitoba in 2006 caused one fatality and numerous injuries.
    Eleven tornadoes have occurred in Manitoba so far this summer. In 2006,
Manitoba experienced 15 tornadoes, compared to a long term (1984-2006) average
of nine tornadoes.
    Canada ranks second in the world for tornado occurrences, experiencing an
average of 80-100 tornadoes annually, compared to an average of 1000-1200 in
the United States each year. The incidence of tornadoes in Canada is likely
higher than that, but because Canada has large, unmonitored and sparsely
populated areas, many more tornadoes may go unreported.
    The science of storms is a priority for Environment Canada, and work is
ongoing to enhance and continuously improve our understanding and knowledge of
severe weather patterns and tornadoes. Environment Canada welcomes videos and
photos of severe weather events. Members of the public willing to share their
images or video may do so via email at storm@ec.gc.ca.

    (Egalement offert en français)

    
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                                 FUJITA SCALE
                       RATING THE SEVERITY OF TORNADOES

    The Fujita scale is used to rate the severity of tornadoes as a measure of
the damage they cause. The scale was devised in 1951 by American meteorologist
Tetsuya (Ted) Fujita. It classifies tornadoes on the following scale.

    F0 light (winds of 64 - 116 km/hr; some damage to chimneys, TV antennas,
    roof shingles, trees, signs, and windows), accounts for about 28% of all
    tornadoes.

    F1 moderate (winds of 117 -180 km/hr; automobiles overturned, carports
    destroyed, and trees uprooted), accounts for about 39% of all tornadoes.

    F2 considerable (winds of 181 -252 km/hr; roofs blown off homes, sheds
    and outbuildings demolished, and mobile homes overturned), accounts for
    about 24% of all tornadoes.

    F3 severe (winds of 253 -330 km/hr; exterior walls and roofs blown off
    homes, metal buildings collapsed or severely damaged, and forests and
    farmland flattened), accounts for about 6% of all tornadoes.

    F4 devastating (winds of 331 - 417 km/hr; few walls, if any, left
    standing in well-built homes; large steel and concrete objects thrown
    great distances), accounts for about 2% of all tornadoes.

    F5 incredible (winds of 418 -509 km/hr; strong frame houses lifted off
    foundations and carried considerable distances; automobile sized objects
    fly through the air in excess of 100 metres; trees debarked; steel
    reinforced concrete structures badly damaged), accounts for about 0.1% of
    all tornadoes. Until the June 2007 Elie tornado, no F5 had been
    officially recorded in Canada. Regardless, F5 tornadoes are possible in
    parts of Canada every summer.

    An enhanced Fujita scale (EF scale) that contains additional damage
guidelines and some modifications to wind speed was developed by the United
States and is now used in that country. Both F and EF scales are essentially
similar in terms of tornado damage ratings. A tornado rated F5 on the Fujita
scale would maintain an EF5 rating on the enhanced Fujita scale.


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                               TORNADO SAFETY

    Because tornadoes can develop very rapidly, it is vital that people know
what to do in a weather emergency to reduce the risk of personal safety and
property.

    - Plan ahead: At home, have a family tornado plan in place, based on the
      kind of dwelling you live in.

    - Be weather alert: Keep an eye on the sky, learn about the signs of
      severe weather, and listen for severe weather watches or warnings.

    - If a tornado threatens, take shelter immediately, preferably in the
      lower level of a sturdy building.

    - Stay away from windows, and outside walls. Flying glass and debris
      poses the largest danger to human safety.

    - If caught outdoors, with no shelter available, lie flat in a ditch,
      ravine or other low lying area, and shield your head with your arms.
    

    For more information about severe weather safety, please visit
Environment Canada's website at http://www.ec.gc.ca.




For further information:

For further information: Dave Carlsen, Warning Preparedness
Meteorologist, Environment Canada, Winnipeg, Manitoba, (204) 983-5871;
Environment Canada Media Relations, (819) 934-8008, 1-888-908-8008


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