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Types
of Severe Weather
The United States is home to an astounding
range of climates and ecosystems, from the frozen tundra of
northern Alaska to the sun-baked desert of southern Arizona.
While we can't cover every type of severe weather in this
space, there are a few common types that are important to
understand:
> Tornadoes
> Hurricanes
> Electrical
storms
The more you know about these three
types, the better your can prepare your family and property
for surviving a storm in safety. If severe weather is approaching
your area now, seek shelter and listen to your radio for emergency
instructions from local officials.
Tornadoes
A tornado is nature's most violent form
of severe weather. With an average wind speed of 112 mph,
they can produce winds up to 300 mph - capable of destroying
all but the strongest structures.
Tornadoes appear most often during spring
when weather patterns are shifting. However, they've been
reported during every month of the year - even in the middle
of winter. Some 800 to 1,000 tornadoes appear in the U.S.
every year, causing millions of dollars in damage and many
deaths.
"Tornado Alley," which runs
from Texas north through east Nebraska and northeast to Indiana,
is the most common site for twisters. However, they can be
found in all 50 states.
Tornadoes usually originate from thunderstorms
that develop when warm, damp air is suddenly lifted by a cold
front or afternoon heating. As this air mass rises, it cools.
Its moisture condenses into rain or freezes into hail. Shifting
air currents within this new storm form areas of rotating
winds that can build up tremendous speed and touch the ground
as tornadoes.
While they can form at any time of day
or night, about 80% of all tornadoes occur between noon and
midnight.
Contrary to what you see in movies,
tornadoes do not "suck" houses, cows, witches on
bicycles, or people up into the funnel. On the other hand,
their strong winds can lift and move large objects such as
a car hundreds of feet. One tornado can devastate an entire
town in less than 5 minutes.
Hurricanes
Hurricanes don't blow as hard as tornadoes,
but they can often cause far more damage because of their
sheer size - sometimes hundreds of miles across. In fact,
the total energy contained in a single major hurricane can
be equal to that of several dozen nuclear bombs. What's more,
one hurricane can spin off many tornadoes if conditions are
right.
Most hurricanes that strike our country
originate in the Atlantic ocean off the coast of West Africa.
They gather strength and speed as they move westward across
the ocean, then northward through the Caribbean Sea toward
the United States. Florida, Texas, the Gulf Coast and the
Carolinas are all familiar with the devastation hurricanes
can bring. Many other states up the Eastern seaboard have
also been hit hard over the years, with most of the damage
coming within 20 miles of the coast.
"Hurricane season" usually
begins in late spring and continues until early November when
the Atlantic waters finally cool off for the winter. Thanks
to advances in satellite technology and weather forecasting,
most hurricanes are tracked far in advance, giving coastal
residents plenty of time to prepare and evacuate when necessary.
Weather officials usually expect anywhere from 5 to 25 "named
hurricanes" per year, with many more tropical storms
as well.
Storm surge is one of the most dangerous
aspects of any major hurricane. Tides can rise suddenly, crashing
billions of gallons of water into unprotected areas. The devastation
you see on television after a major hurricane is usually caused
by both wind and water. It's this deadly combination that
some people forget when they try to "ride out" the
storm.
Electrical
Storms
Thunderstorms aren't as deadly as tornadoes,
but they occur far more often and can cause tremendous damage.
A large thunderhead cloud is capable of discharging billions
of volts of electrical energy - enough to start a major fire,
knock out a communications system or bring down an airplane.
The electronic appliances we depend on today are often the
most vulnerable to electrical storms.
Most thunderstorms last for less than
an hour, and they typically occur during spring and summer
when conditions are right. Upper atmosphere collisions between
low-pressure and high-pressure fronts can produce a long line
of thunderstorms stretching for dozens - even hundreds - of
miles.
While thunderstorms may be entertaining
to watch, they carry a deadly threat that should never be
ignored. Every year, dozens of Americans are killed or seriously
injured by lightning strikes. Tragically, most of these deaths
could have been avoided.
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