Transcript Natural Disasters

Around the world
Hurricane
• A hurricane is a powerful storm system with a large low
pressure center that produces intense winds and heavy
rainfall
• Most hurricanes rage harmlessly in the sea
• Hurricane season in the Atlantic Ocean runs from June 1
to November 30.
• Hurricanes have male and female names, but at one
point only female names were used.
What is a natural disaster?
• Natural disasters are the effects of natural
hazards.
• There are lots of different types of natural
disasters such as a tornado.
Volcanoes
• A volcano is an opening, or rupture, in a planet's surface
or crust, which allows hot Magma, Volcanic Ash and
gases to escape from below the surface.
• Volcanoes are generally found where tectonic plates are
diverging or converging.
Tornados
• A tornado (often referred to as a twister or, erroneously,
a cyclone) is a violent, dangerous, rotating column of air
that is in contact with both the surface of the earth and a
cumulonimbus cloud or, in rare cases, the base of a
cumulus cloud.
• Tornado winds can reach 300 miles per hour. They
cause damage when they touch down on the ground
Earthquakes
• Earthquakes happen when the moving techtonic plates
that make up the surface of the Earth move apart or
bump into each other, or slide under each other. This
movement tears apart the surface of the Earth, or
crunches it up. Most often, this just means a little
shaking for a few seconds, and nothing very serious
happens.
• Because most of the Earth is covered by oceans,
earthquakes often happen in the ocean. Usually this just
shakes the water and people don't notice. But
sometimes the water pulls all together into a huge wave
called a tsunami
Tsunami
• A tsunami is a series of huge waves that happen after an
undersea disturbance, such as an earthquake or volcano
eruption.
• The waves travel in all directions from the area of
disturbance, much like the ripples that happen after
throwing a rock.
• The waves may travel in the open sea as fast as 450
miles per hour. As the big waves approach shallow
waters along the coast they grow to a great height and
smash into the shore.
Forest Fires
• Fires can sweep through cities and rural areas alike.
Woodland fires can burn at up to 800°C and spread at
up to 100 metres per minute, swiftly destroying an entire
area.
• Common causes of wildfires include lightning, human
carelessness, arson, volcano eruption, and pyroclastic
cloud from an active volcano. Heat waves, droughts, and
cyclical climate changes such as El Niño can also have a
dramatic effect on the risk of wildfires.
Floods
• A flood is an overflow of an expanse of water that
submerges land. The EU floods directive defines a flood
as a temporary covering by water of land not normally
covered by water.
• Flooding may result from the volume of water within a
body of water, such as a river or lake, which overflows or
breaks levees, with the result that some of the water
escapes its usual boundaries
Whirlpool
• A whirlpool is a swirling body of water usually produced
by ocean tides. The vast majority of whirlpools are not
very powerful. More powerful ones are more properly
termed maelstroms.
• In the case of powerful waterfalls, like Niagara falls ,
these whirlpools can be quite strong. The most powerful
whirlpools are created in narrow shallow straits with fast
flowing water.
• Powerful whirlpools have killed unlucky seafarers, but
their power tends to be exaggerated by laymen.
Avalanche
• An avalanche is a sudden rapid flow of snow down a
slope, occurring when either natural triggers or human
activity causes a critical escalating transition from the
slow equilibrium evolution of the snow pack.
• Typically occurring in mountainous terrain, an avalanche
can mix air and water with the descending snow.
Powerful avalanches have the capability to entrain ice,
rocks, trees, and other material on the slope.
• Avalanches are primarily composed of flowing
snow, and are distinct from mudslides, rock
slides, and serac collapses on an icefall.