Snowstorms
Snow can transform the world into a winter wonderland,
but it can also be deadly. 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 village of Gultur,
destroying everything in its path and crushing 30 people
to death.
What Is Snow?
Snow forms when tiny ice crystals in clouds
stick together and form snowflakes. This
happens very high up where the air’s
temperature 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. Some places are so cold that the snow
stays there all year round!
Snowflakes come in an amazing variety of shapes, but usually have six
sides. No one has ever found two the
Drivers Beware!
Apart from avalanches, the other main hazard from 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
if you find yourself in these conditions.
Most people enjoy snow, as long as they wrap up well in
warm clothes, but if you live next to an old person, why
not offer to clear the snow from their garden path. Then
they won’t slip and fall over when they go out.
Tornadoes
One of the most spectacular forms of extreme weather
are tornadoes! People love them so much they will go on
tornado or twister chasing holidays driving around in
metal armoured cars!
What Is A Tornado?
A tornado is like a gigantic, whirling vacuum cleaner that can suck
up anything they touch, including farm animals, people and even
cars. It is the most violent concentration of energy the atmosphere can produce. As a tornado picks up torn off branches and
parts of buildings, the debris flies around the funnel at high speed,
smashing into other things.
Where Do Tornadoes Happen?
Tornado Alley
Nearly all tornadoes
happen in a part of the
U.S.A. called “Tornado
Alley”. However, they
can develop over most
of the world. In the
U.K., there are about 60
a year! If a tornado
forms over water, it
sucks up large amounts
of water and is called a
waterspout.
Though most tornadoes have quite narrow funnels, if they
hit your house, they can cause lots of damage, ripping off
roofs and blowing out windows. In Tornado Alley, houses
are built with an underground cellar with a strong door so
that even if you house above ground is destroyed you will
survive!
Thunderstorms
FLASH……...BOOM! (Scream!) If you go to school in
Thailand, every so often you will see, hear and feel a very
exciting form of weather… thunderstorms!
What Is Thunder And Lightning?
The flash, called lightning, is what we see when a gigantic spark of
powerful electricity jumps from a storm cloud to the ground. The
boom we hear, the thunder, is caused when the lightning
superheats the air it is travelling through, making it explode
outwards. This causes a very loud sound wave that can be heard
miles away.
Why Does Lightning Come Before Thunder?
Light waves travel very, very fast!
)))))))))))
Sound waves are much slower.
The light reaches the boy before the sound.
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. So unless your
thunderstorm is directly above you we usually see the flash
before we hear the bang.
Though thunder and lightning can be exciting, the energy
released by the lightning is so powerful, it could kill
anyone it hits. So when a thunderstorm starts, you should
get out of a swimming pool, get under a solid shelter.
Don’t shelter under a tree or stand up on open ground.
Hurricanes
Board up your windows! Stay indoors! A hurricane is
coming your way! Hurricanes are the biggest, most violent
and most destructive storms our planet is capable of
producing.
What Is A Hurricane?
From space you can clearly see the eye
of this hurricane about to hit the United
States.
Hurricanes form from small storms over
tropical oceans. Fed by humid air rising
from the warm ocean and the rotation of
the earth, they grow into a monstrous
swirling mass of cloud as they drift
westward. The most deadly winds occur 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.
Storm Surge
Most people who die in hurricanes are killed by the sea. The eye
of the storm sucks up the sea beneath it by as much as 6m. At the
same time, violent winds whip up waves as tall as houses. These
two things together produce a “storm surge” - towering walls of
sea water that surge inland for kilometres, sweeping away boats,
trees and buildings.
Though Thailand is generally safe from hurricanes, earlier
this year a hurricane that hit the Philippines and Vietnam
went on to reach Thailand. Though the hurricane has lost
most of its power and we didn’t experience the high winds
the other countries did, we did get 3 days of almost continual rain! All the student and staff had to carry
umbrellas and be prepared for rainy playtimes.