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SEVERE WEATHER

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SEVERE WEATHER Tornado Facts Tornado Facts Thunderstorms are small, intense weather systems that produce strong winds, heavy rain, lightening, and thunder. – PowerPoint PPT presentation

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Title: SEVERE WEATHER


1
SEVERE WEATHER
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Thunderstorms are small, intense weather systems
that produce strong winds, heavy rain,
lightening, and thunder. Thunderstorms form when
warm air is forced upward at a cold front.
Cumulonimbus clouds also form on hot, humid
afternoons in the sprig and summer. In both
cases, the warm, humid air rises rapidly. As
the air rises, it cools, forming dense
thunderheads.
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THUNDERSTORMS
2 atmospheric conditions are required to
produce thunderstorms warm and moist air
near Earths surface an unstable
atmosphere The air is unstable when the
surrounding air is colder than the rising air
mass. The air mass will continue to rise as long
as the surrounding air is colder than the air
mass.
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When the warm rising air reaches its dew point,
the water vapor in the air condenses and forms
cumulus clouds. If the air is extremely
unstable, the air will continue to rise which
causes the cloud to grow into a dark,
cumulonimbus cloud.
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Thunderstorms are very active electrically. Light
ning is an electric discharge that occurs between
a positively charged area and a negatively
charged area.
  • Lightning can happen between
  • two clouds
  • between earth and a cloud
  • two parts of the same cloud

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When lightning strikes, energy is released. This
energy is transferred to the air and causes the
air to expand rapidly and send out sound
waves. Thunder is the sound that results from
the rapid expansion of air along the lightning
strike.
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Severe Thunderstorms can produce 1 or more of
the following high winds hail flash
floods tornadoes
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Flash flooding that results from heavy rains
causes millions of dollars in property damage
annually.
Flash flooding is the leading cause of
weather-related deaths.
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Lightning is responsible for starting thousands
of forest fires each year and killing or injuring
hundreds of people each year in the United
States.
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TORNADOES
Tornadoes happen in only 1 of all
thunderstorms. A tornado is a small, spinning
column of air that touches the ground. A tornado
starts out as a funnel cloud and hangs in the
air. The funnel cloud becomes a tornado when
it makes contact with the Earths surface.
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About 75 of the worlds tornadoes happen in the
United States. Most of these happen in the
spring and early summer when cold, dry air from
Canada meets warm, moist air from the
Tropics. Although they only last a few minutes
they can cause a lot of damage due to their
strong, spinning winds. Average tornado wind
speeds are between 120 and 180 km/h.
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Tornado Facts
Texas holds the record for the most tornados
178 in 2004 Ohio averages 16 tornadoes a year and
five tornado-related deaths. Ohios worst
Tornado was in Xenia, Ohio in 1974 33 people
were killed

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HURRICANES
A large, rotating weather system that has wind
speeds at least 120 km/h is called a
hurricane. Hurricanes are the most powerful
storms on Earth. Hurricanes have different names
is different parts of the world. In the western
Pacific Ocean typhoons Over the Indian Ocean
cyclones
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Most hurricanes form in the areas between 5 and
20 north latitude and between 5 and 20 south
latitude over warm, tropical oceans. At higher
altitudes, the water is too cold for hurricanes
to forms. A hurricane begins as a group of
thunderstorms moving over tropical ocean
waters. Winds traveling in 2 different
directions meet and cause the storm to
spin. Because of the Coriolis Effect, the storm
turns counterclockwise in the Northern hemisphere
and clockwise in the Southern hemisphere.
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Defining a Hurricane According to the National
Hurricane Center, "hurricane" is a name for a
tropical cyclone that occurs in the Atlantic
Ocean. "Tropical cyclone" is the generic term
used for low-pressure systems that develop in the
tropics. "Tropical cyclones with maximum
sustained surface winds of less than 17 meters
per second (39 mph) are called tropical
depressions. Once the tropical cyclone reaches
winds of at least 17 meters per second, it is
typically called a tropical storm and assigned a
name. If winds reach 33 m/s (74 mph), then it is
called a "hurricane."
Hurricanes are defined by the following
characteristics They are tropical, meaning
that they are generated in tropical areas of the
ocean near the Equator. They are cyclonic,
meaning that their winds swirl around a central
eye. Wind direction is counterclockwise (west to
east) in the Northern Hemisphere and clockwise
(east to west) in the Southern Hemisphere (more
about this later). They are low-pressure
systems. The eye of a hurricane is always a
low-pressure area. The lowest barometric
pressures ever recorded have occurred inside
hurricanes. The winds swirling around the center
of the storm have a sustained speed of at least
74 mph.
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HOW A HURRICANE FORMS A hurricane gets energy
from the condensation of water vapor. Once
formed, ,the hurricane is fueled through contact
with the warm ocean water. Moisture is added to
the warm air by evaporation from the ocean. As
the warm, moist air rises, the water vapor
condenses and releases large amounts of
energy. The hurricane continues to grow as long
as its over the source of warm, moist air. When
it moves into colder waters or onto land, it
begins to die because it has lost its source of
energy.
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Katrina's eyewall swirls in a photograph by a
National Oceanic and Atmospheric Administration
(NOAA) P-3 hurricane hunter pilot on August 28,
2005, a day before the powerful storm slammed
into the United States Gulf Coast.
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During the last 35 years, the number of Category
4 or 5 Hurricanes have doubled, which researchers
have linked to global warming. You would think
that with the overwhelming evidence of increased
temperatures affecting our planet, there would be
no longer any doubts that this is being caused by
global warming. Yet there are still a large
number of people (and scientists) who either rule
this out completely, or reluctantly admit that
maybe there is some connection or link, but
usually insist on telling us that there is
nothing to worry about.
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Hurricane Damage
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THUNDERSTORM SAFETY
Lightning is one of the most dangerous parts of a
thunderstorm. Lightning is attracted to tall
objects so if outside, stay away from trees.
If you are in the open crouch down. Stay away
from bodies of water!
30
TORNADO SAFETY
A watch a weather alert that lets people know
that a tornado may happen A warning a weather
alert that lets people know that a tornado has
been spotted
Find shelter quickly
31
FLOOD SAFETY
A flash flood is a flood that rises and falls
very suddenly. Best thing to do find a high
place to wait out the flood!
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HURRICANE SAFETY
People living in the area may be asked to
evacuate. You and your family should have A
disaster supply kit that Includes enough water
and food to last a few days. To protect your
windows You should cover them with
Plywood. Stay inside your home!
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