Transcript Ontario`s Most Expensive Disaster.

Ontario’s Most Expensive
Weather Disaster
August 19, 2005.
By Charmaine Hachey
On the afternoon of
August 19, a line of
severe
thunderstorms and
F2 tornados
appeared in Fergus
Ontario.
Lightning and the CN in Ontario.
Several tornadoes were popping at any
one time. At it’s worst, the storm produced two
F2 tornadoes with gusts between 180 and 250
km/h. These tornadoes uprooted hundreds of
trees, chewed the limbs off of countless others,
downed power lines, tossed cars and trucks
aside, and ripped into several homes, cottages
and barns.
The storm that hit Ontario (Fergus)
featured torrential rains, quarter- to golfball size hail, strong straight-line winds and
flash flooding
Fujita Scale- Tornado Scaling
F2 - considerable winds of 181 to 252 km/hr;
roofs blown off homes, sheds and outbuildings
demolished, and mobile homes overturned. F2
tornadoes account for about 24 percent of all
tornadoes.
The tornados
which hit
Ontario were
classed as F2
Tornados.
Overall, Ontario’s most expensive weather disaster coasted
over $500 million dollars.
Steeles Avenue in Toronto after August 19th storm.
Signs of a Tornado
-A sickly greenish or greenish black color to the sky.
-A strange quiet that occurs within or shortly after the
thunderstorm
-Clouds moving by very fast, especially in a rotating
pattern or converging toward one area of the sky.
Signs of a Tornado, II
-A sound a little like a waterfall or rushing
air at first, but turning into a roar as it
comes closer. The sound of a tornado has
been likened to that of both railroad trains
and jets.
-Debris dropping from the sky
-An obvious "funnel-shaped" cloud that is
rotating, or debris such as branches or
leaves being pulled upwards, even if no
funnel cloud if visible.
What Causes Thunder and Lightning?
Thunder and lightning are usually paired together. Thunder
though, is actually caused by lightning. Lightning is a giant
spark. A single stroke of lightning can heat the air around it
to 30,000 degrees Celsius. This extreme heating causes the
air to expand at an explosive rate. The expansion creates a
shock wave that turns into a booming sound wave, which we
call thunder.
What causes a tornado
When the ground is warmer, and the air above, is colder,
warm air near the surface rises. As it cools, the water vapor
it carries, condenses causing clouds and thunderstorms.
Winds near the surface blow in one direction, while winds
aloft, blow in the opposite direction. The difference causes a
“horizontally rotating mass of air”. Rising warm air creates
and updraft, pulling the rotating air upright. The funnel of a
tornado starts above and drops down to a region air pressure
is lower.
Sources
http://www.msc-smc.ec.gc.ca/media/top10/archive_e.html
http://www.citynoise.org/article/1908
http://www.ec.gc.ca/EnviroZine/english/issues/61/feature1_e.cfm
http://ontario.hazards.ca/historical/Tornado_Ontario-e.html