NATURAL DISASTERS

IN THE UNITED STATES

NATURAL DISASTERSWhat is a natural disaster?

• Is what happens when nature causes damage.

• A hurricane can be a natural disaster.

• Most natural disasters happen suddenly.

• They can wreck homes and property.

• People can get hurt.

VOLCANOES• A hole in the earth’s crust from which

hot or melted rock and steam come

• The word “volcan” in Roman mythology means god of fire.

• Many are found in a big curve that goes around the Pacific ocean. The scientists name the curve The Ring.

• The liquid inside the volcano is called magma. It is hot melted rock. When it is out the volcano’s mouth is called lava.

CYCLONES

• It often cover thousands of square miles.

• The winds blows toward the center of an area of low air pressure.

• Cyclones blow in spirals because of the rotation of the earth.

• The direction of turn is counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere.

TORNADOS• Sometimes miscalled cyclones, arise when

conditions that cause thunderstorms are usually violent.

• Winds blowing in opposite directions around a strong updraft start a narrow, violent whirl.

• Centrifugal force throws the air away from the center, leaving a core of very low pressure.

THUNDERSTORMS

• Are local disturbances usually covering only a few square miles.

• Extremely common in many parts of the world. Most of North America.

• Composed of one or more meteorologists call cells.

• The duration of thunderstorm is short, usually lasting only 30 to 40 minutes.

EARTHQUAKES

• The sudden shaking of the ground that occurs when masses of rock change position below the earth’s surface is called an earthquake.

• The shifting masses send out shock waves that may be powerful enough to alter the surface of the earth.

Earthquakes in the united states(In 1906 the SAN FRANCISCO)• San Francisco

earthquake, when 521 blocks in the city burned uncontrollably for three days.

• San Francisco, California in 1989 an earthquake caused great destruction and lost

HURRICANES• Any wind that blows

more than 75 miles per hour.

• Characterized by strong winds and torrential rains.

• After it roars ashore, it looks like at though the storm has ended when the eye passes overhead.

SIGNS OF A HURRICANE• First come dull sunset, caused by a thin haze

of clouds.• Then the air becomes hot and sticky.• The barometer is high, and the winds dies.• At sea there is a growing swell.• Next the barometer drops suddenly, signaling

a rapid change from high pressure to low pressure.

• last a deluge of rain fills the air with strong winds.

HURRICANES IN THE UNITED STATES

• Lake okeechobee, Florida in Sept. 16-17, 1928. Miles of dikes collapsed; lake spilled onto farmland.

• In New England in September 23, 1938. Damage homes and crop.

HURRICANES IN U.S.CONTINUES...

• On June 27, 1957 in Louisiana. Hurricane Andrew slammed into the Golf coast but residents ignored warnings and threw parties instead of evacuating. More than 7000 people die.

• In August 14-22, 1969 in the U.S. Gulf coast hurricane Camille roared through Louisiana, Mississippi and Alabama. More than 500, 000 people death.

MORE HURRICANES IN U.S.

• In September 16-22, 1989 hurricane Hugo wreaked path of destruction through Caribbean island lashing South and North Carolina. More than people 500 dead and the damage of property was estimated in the billions of dollars.

• In September 1992, the Hawaiian Island was hit by hurricane Iniki. The winds were 225 miles per hour. Estimated $2 billion in property damage.

CYCLONE

• Winds blow toward the center of an area of low air pressure.

• They blow in spirals.• They are deflected by

the rotation of the earth.

• The direction is clockwise counterclockwise