Transcript Hurricane Power Point

Hurricanes
It’s a day late in the summer. You hear the sounds of pounding hammers and buzzing
saws. Some people are fixing roofs, others are cutting up trees. A hurricane struck last
night. Wind ripped at the town for hours, objects were sent flying, and rain poured
down. Fortunately people paid attention to the weather forecasts and left town.
What causes such powerful storms?
What are Hurricanes?
•A hurricane is a type of storm with lots of energy.
•These storms usually form in the tropics, the part of the Earth near
the equator.
•It gets the energy from air moving upward over warm ocean water.
•A hurricane is a dangerous storm with wind speeds of at least 119
kilometers per hour.
•Many bands of thunderstorms and rain wrap around the center.
Hurricane Andrew
•In august 1992, an area of low pressure formed over the Atlantic ocean.
•It gained strength and became a tropical storm.
•People gave it a name – Andrew
•Hurricane Andrew moved West across the ocean.
•It smashed into the Bahama Islands in the Caribbean Sea.
Hurricane Andrew
•The United Stated was next.
Hurricane Andrew
•On August 24th, the hurricane slammed into Florida.
•Winds may have reached 250 kilometers per hour.
Hurricane Andrew
•In about 4 hours, Andrew swept across southern Florida.
Hurricane Andrew
•It weakened over land
•but it regained strength as it moved over the warm water
of the Gulf of Mexico.
Hurricane Andrew
•The hurricane then crashed into Louisiana
Hurricane Andrew
•Then Andrew moved northward over land. It’s winds
quickly weakened, but it’s rains still flooded many areas.
Hurricane Andrew approaching the Bahamas and Florida as a
category 5 hurricane.
An entire Miami Neighborhood flattened
Storm surge measured 16.5 feet above sea level.
Satellite image of Andrew approaching Louisiana
A tropical storm needs special conditions before it can form.
It needs wind
blowing
towards the
low pressure
It needs an
area of low
pressure
It needs a
large area of
warm ocean
water
Tropical Depression
Thunderstorms grow out of a tropical depression
as the wind increases and begins to swirl.
The wind speeds can reach 61 kilometers per hour.
Tropical Storm
Air pressure at the ocean’s surface drops. Surface winds
blow faster and begin to swirl. A tropical storm develops.
Hurricane
Thunderstorms begin to move in spiral bands. Air
pressure drops lower, and surface winds blow faster.
The tropical storm is now a hurricane.
What’s in a Name?
•To tell listeners about several different storm systems,
the National Hurricane Center uses a list to name the
storms.
•Female and male names follow one another
in alphabetical order.
• A tropical storm gets a name when its winds reach 63
kilometers per hour.
•If the storm becomes a hurricane, it keeps that name.
•The name may be used again unless the storm causes
severe damage. Then another name that starts with
the same letter is used.
•All hurricanes have strong thunderstorms and fast,
swirling winds.
• As you can see in the table, hurricanes are classified by
their wind speed.
The strong winds of hurricanes cause incredible damage and can be
compared to other types of storms.
Hurricanes
A hurricane can
be hundreds of
kilometers across.
 It has many
thunderstorms.
 A hurricane
forms over the
ocean.
 It can last for
many days.
Both
Strong storms.
 Both spin
around a center
of low air
pressure.
 has high winds
and can cause
great damage.
 affect all of
Earth’s systems.
Tornadoes
A tornado is
usually hundreds of
meters across.
It forms within a
single thunderstorm.
Almost all form
over land.
 Most last only a
few minutes.
winds can be
much faster
Let’s see how
much you
remember!
Try the quiz.
Hurricane
Tornado
Storm surge
The ocean water that a
hurricane can push onto land
is a ______.
Tropical storm
Tropical
depression
Vortex
Hurricane
Tornado
Storm surge
A ______ has wind speeds of
at least 119 kilometers per
hour.
Tropical storm
Tropical
depression
Vortex
Hurricane
Tornado
Storm surge
A hurricane keeps the name it
was given when it became a
______.
Tropical storm
Tropical
depression
Vortex
Hurricane
Tornado
Storm surge
A low pressure air mass with
storms that have winds that
begin to spin over warm ocean
water is a ______.
Tropical storm
Tropical
depression
Vortex
Hurricane
Tornado
Storm surge
A rapidly spinning column of
air that comes out of a
thunderstorm and touches the
ground is a ______.
Tropical storm
Tropical
depression
Vortex