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Severe Weather
Thunderstorms
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A thunderstorm is an intense local storm that forms
strong winds, heavy rain, lightning, thunder, and
sometimes hail
Thunderstorms
~There are three stages to
a thunderstorm
Stage 1 – Warm humid air
rises in an updraft, creating
cumulus clouds.
Stage 2 - Ice particles may
form at the top of the cloud.
They fall and pull cold air
down, creating a downdraft
and heavy rain or hail.
Stage 3 – The storm slows or
ends as the downdraft
prevents more warm air
from rising.
Thunderstorms
Lightning is an electric
discharge that happens
between positively and
negatively charged areas.
Electrical charges build up near
the tops and bottoms of
clouds as pellets of ice move
up and down through the
clouds.
Thunder is the sound created
by the rapid expansion of air
along a lightning strike.
Let's watch
https://www.youtube.com/watch?v=Xou6iwfeNk
Tornadoes
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A tornado is a violent rotating
column of air extending from
a thunderstorm to the
ground.
Tornadoes are capable of
tremendous destruction with
wind speeds of up to 300
mph.
Tornadoes can happen
anywhere, but are most
likely in an area called
'tornado ally' in the midwest
states.
Tornadoes
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Tornadoes form when a cool,
dry air mass collides with a
warm, moist air mass.
How the column of air begins to
rotate is not completely
understood by scientists,
but one way the rotation
appears to happen is when
winds at two different altitudes
blow at two different speeds
creating wind shear.
For example, a wind at 1000
feet above the surface might
blow at 5mph and a wind at
5000 feet might blow at 25mph.
This causes a horizontal
rotating column of air.
Let's Watch
https://www.youtube.com/watch?v=pSajNLBH7
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Hurricanes
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Hurricanes are tropical
storms. They take place in
the tropical climate zone.
•
Hurricanes form over the
ocean from late spring to
early fall.
•
Hurricanes can be huge,
spanning up to 600 miles
across.
•
Hurricanes have very
strong winds that spiral
inward at speeds of 75 to
200 miles per hour.
Hurricanes
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Hurricanes form in areas of low pressure where the ocean
water is warm.
•
The warm ocean water evaporates and causes cloud
formation.
•
As more water evaporates more clouds form, as the warm air
is pushed upward the clouds begin to spin around a center
called the eye, where fair weather and light winds can be
found.
Hurricanes
High winds and tornadoes
can result from
hurricanes causing
massive damage.
A storm surge is a huge
mass of ocean water
that gets pushed onto
coastal areas, causing
sea level to rise several
meters.
Damages can take months
to clean up.
Let's watch
https://www.youtube.com/watch?v=k35Gwb0FF
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How to be prepared for severe
weather.
•
If there are bad weather conditions take shelter indoors.
•
Be aware of what types of severe weather can occur where
you live.
•
Pay attention to watches and warnings from local weather
stations.
•
Know the safest place in your house to wait out a storm.
This will usually be a basement or an interior room without
windows.
•
Keep an emergency kit ready just in case.
•
If necessary have a plan to leave home in case of
emergency evacuation.