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Transcript of Tornadoes - primarysite-prod-sorted.s3.amazonaws.com€¦ · Tornadoes Did you know that tornadoes...
Tornadoes Did you know that tornadoes are one of the most spectacular forms of ex-
treme weather on the planet? A tornado is a furiously whirling funnel that can
suck up anything in its path. Amazingly, they have even been known to crush
entire towns!
How does a tornado form?
Most tornados form from thunderstorms. When warm air and cool air meet,
they create an unstable atmosphere. Air rises gradually and starts to rotate. If
a tornado picks up torn off branches and parts of buildings, the debris flies
chaotically around the funnel at high speed. Scientists still don’t understand
how and why tornados finish, but they are still researching and learning more
about this incredible phenomenon.
Are tornadoes dangerous?
Although most tornadoes
have quite narrow funnels,
they can cause a lot of
damage if they hit your
house… violently ripping off
roofs and destructively
blowing out windows. In
Tornado Alley, houses are
built with an underground
cellar with a strong door so
that you can shelter and
survive if a tornado hits.
Tornado Alley
Snowstorms Snowstorms can transform the world into a winter wonderland, but
they can also be deadly. This extreme weather has even been known
to destroy entire villages! On the afternoon of 23rd February 1999, a
slab of snow weighing 170,000 tonnes broke away from an Austrian
mountain slope forming a deadly avalanche. It roared toward the vil-
lage of Gultur, destroying everything in its path and crushing 30 peo-
ple to death.
How does snow form?
Snow forms when tiny ice crystals in clouds
stick together and gradually form snowflakes.
This happens very high up where the air’s tem-
perature is below 0°C, the freezing point of
water. If the air close to the ground is also
cold, the snow will settle there and not melt.
Amazingly, some places are so cold that the
snow stays there all year round!
Are snowstorms dangerous?
Apart from avalanches, snow can effect travellers in cars. Drivers
need to be especially careful not to slip and slide around on the icy
roads. During heavy snowstorms, it is possible there is so much
snow that you can hardly see in front of your vehicle. This is called a
“white out”. Slow right down and drive carefully if you find yourself
in these conditions.
Snowflakes come in an amazing varie-
ty of shapes, but usually have six
sides. No one has ever found two the
same.
Thunderstorms When the air around you feels muggy, when a rumble can be heard, when a light
pieces the sky… beware, because a thunderstorm is on its way! Thunderstorms
are very loud, and have been known to cause chaos among people all over the
world.
How do thunderstorms form? The flash, called lightning, is what we see when a gigantic spark of powerful elec-
tricity jumps from a storm cloud to the ground. When lightning superheats the
air, the air explode powerfully outwards. Interestingly, this causes a very loud
sound wave that can be heard miles away.
Why Does Lightning Come Before Thunder?
The light created in a lightning bolt travels at the speed of light: 300,000 km per
second. Sound waves are roughly a thousand times slower travelling about 300
km per second. Unless a thunderstorm is directly above you, we usually see the
flash before we hear the bang.
Although thunder and lightning can be exciting, the energy released by the light-
ning is so powerful that it has been known to kill anyone it hits. While a thunder-
storm is raging, you should get out of swimming pools and ensure you are under a
solid shelter. Don’t shelter under a tree or stand up on open ground.
L i g h t w a v e s t r a v e l v e r y , v e r y f a s t !
))))))))))) Sound waves are much slower. The light reaches the boy before the sound.
Are thunderstorms dangerous?
Hurricanes Board up your windows! Stay indoors! A hurricane is coming your
way! Hurricanes have caused destruction in all over the world. They
are the largest, most violent and most destructive storms our planet
is capable of producing.
How do hurricanes form?
Hurricanes form from small storms over
tropical oceans. Fed by humid air ris-
ing from the warm ocean, they grow into a
monstrously swirling mass of cloud as they
drift westward. The most deadly winds oc-
cur in the eye wall, a circular wall of cloud
surrounding a central hole called an eye.
Winds speeds can reach more than 240 km
per hour in the eye wall.
Are hurricanes dangerous? Most people who die in hurricanes are killed by the sea. The eye of
the storm has been known to powerfully suck up the sea beneath
it by as much as 6m. At the same time, chaotically swirling winds
gradually whip up waves as tall as houses. These two things to-
gether produce a “storm surge” - towering walls of sea water that
surge inland for kilometres, sweeping away boats, trees and build-
Although the UK hasn’t experienced any hurricanes, many countries
in Asia and South America are not as lucky. Interestingly, the ef-
fects of hurricanes can often be felt in nearby countries. For exam-
ple, a recent hurricane in the Philippines caused 3 days of almost
continual rain in Thailand!
From space you can clearly see the eye
of this hurricane about to hit the United
States.