AWCN12 CWTO 231507
WEATHER SUMMARY FOR NORTHERN ONTARIO
ISSUED BY ENVIRONMENT CANADA TORONTO
 AT 10:14 AM EDT SATURDAY 15 AUGUST 2009.
SUMMARY OF THE TORNADO OUTBREAK OVER ONTARIO ON AUGUST 20.
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==WEATHER EVENT DISCUSSION==
A TRIPLE BARRELLED SEVERE WEATHER OUTBREAK STRUCK ONTARIO
THURSDAY.
SHORTLY AFTER NOON A SUPERCELL STORM DEVELOPED JUST SOUTH
OF LAKE HURON. THIS CELL TRACKED NORTHEASTWARD FOR A REMARKABLE 200
KM PRODUCING THE DURHAM AND THORNBURY TORNADOES. THE STORM
CELL FINALLY WEAKENED OVER GEORGIAN BAY TOWARD EVENING.
AT THE SAME TIME A SQUALL LINE DEVELOPED OVER LOWER MICHIGAN THEN
TRACKED ACROSS SOUTHERN ONTARIO DURING THE AFTERNOON AND EVENING
HOURS. THIS FEATURE PRODUCED STRAIGHT LINE WIND DAMAGE TO SEVERAL
LOCALES FROM WINDSOR TO WELL NORTHEAST OF TORONTO AS WELL AS THE
DESTRUCTIVE VAUGHAN AND NEWMARKET TORNADOES.
FINALLY IN THE EARLY EVENING AN ISOLATED SUPERCELL STORM DEVELOPED
NORTHEAST OF GEORGIAN BAY AND TRACKED NORTHEASTWARD TO PRODUCE A
POSSIBLE TORNADO OVER THE AREA BETWEEN ARNSTEIN AND NORTH BAY AS
WELL AS A WATERSPOUT OVER LAKE NIPISSING.
 THERE WAS ONE FATALITY WITH THE TORNADO IN THE SOUTH END OF DURHAM.
SEVERAL OF THE TORNADOES WERE RATED AS F2 DAMAGE ON THE FUJITA
SCALE. F2 DAMAGE IS EQUIVALENT TO WIND STRENGTH OF 180 TO 250 KM/H.
THE FOLLOWING IS A LIST OF TORNADOES AND ASSOCIATED DAMAGE ASSESSED
BY FOUR SEPARATE ENVIRONMENT CANADA STORM DAMAGE TEAMS.
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DATE
TORNADO LOCATION/PATH                       DAMAGE OVERVIEW
TORNADO 1   5 KM SW OF DURHAM TO MARKDALE   F2 TORNADO DAMAGE
(CONFIRMED) (ROUGHLY 20 KM)                 (SIGNIFICANT HOUSE
                                            + TRAILER DAMAGE,
                                            TREES DOWN)
TORNADO 2   FROM SOUTH OF THORNBURY TO THE  F2 TORNADO DAMAGE
(CONFIRMED) SOUTHEAST OF THORNBURY (PATH    (DETAILS UNCERTAIN
            LENGTH UNKNOWN)                 AT THIS TIME)
TORNADO 3   WOODBRIDGE/VAUGHAN              F2 TORNADO DAMAGE
(CONFIRMED) (SEVERAL KM LONG                (HUNDREDS OF HOMES
            + 50 METRES WIDE)               DAMAGED, TREES DOWN,
                                            CARS FLIPPED)
TORNADO 4   NEWMARKET AREA                  F1 TORNADO DAMAGE
(CONFIRMED)                                 (HOCKEY ARENA ALMOST
                                            DEMOLISHED)
TORNADO 5   ARNSTEIN TO RESTOULE TO NORTH   WATERSPOUT/TORNADO
(PROBABLE)  BAY (PATH LENGTH UNKNOWN AT     SIGHTINGS (DAMAGE DETAILS
            THIS TIME)                      UNCERTAIN AT THIS TIME)
TORNADO 6   MILTON                          F1 DAMAGE
(POSSIBLE)                                  (SOME ROOF DAMAGE)
ENVIRONMENT CANADA CONTINUES TO EVALUATE THE DAMAGE FROM THE STORMS.
AN INVESTIGATION IS BEING CONDUCTED ON REPORTED DAMAGE IN THE
GRAVENHURST AREA TODAY.
END/OSPC