My name is Vishana
Baskaran and today I am
presenting to you a PPT on
3. What is a Hurricane?
A hurricane is a tropical storm that forms over warm ocean waters. Not all
hurricanes reach land. But, if they do they bring powerful winds and rain. Hurricanes are
storms of extraordinary violence characterized by spiraling, rain-bearing winds of at least
74 miles (119 kilometers) per hour. Hurricanes are not always called “hurricanes".
In eastern Asia near China, they call it “typhoons”. In North America, they call it “hurricane".
Near India, they call it “cyclones”. People living in the Philippines call them “bagnios”. In
Australia, they call them willy-willies. Hurricanes happen all over the world!
4. How do the Hurricanes Form?
Hurricanes use warm, moist air as fuel. That is why they form only over warm
ocean waters near the equator. The warm, moist air over the ocean rises upward
from near the surface. Because this air moves up and away from the surface, there
is less air left near the surface.
Air from surrounding areas with higher air pressure pushes in to the low pressure
area. Then that "new" air becomes warm and moist and rises, too. As the warm air
continues to rise, the surrounding air swirls in to take its place. As the warmed,
moist air rises and cools off, the water in the air forms clouds. The whole system of
clouds and wind spins and grows, fed by the ocean's heat and water evaporating
from the surface.
As the storm system rotates faster and faster, an eye forms in the center. It is very
calm and clear in the eye, with very low air pressure. Higher pressure air from
above flows down into the eye.
When the wind speeds reach 74 mph, the storm is officially a hurricane.
Hurricanes usually weaken when they hit land, because they are no longer being
"fed" by the energy from the warm ocean waters.
7. The Parts of a Hurricane
A hurricane has many parts to it. The structure of a hurricane consists of the eye,
eyewall and outer rain bands. The eye of the storm is in the center and is very calm,
unlike the other parts. The most dangerous winds of a hurricane occur inside the
eyewall. The eyewall encloses the eye surrounding thunderstorms. Large bands of
clouds and precipitation spiral from the eye wall and are thusly called spiral rain
The rain bands
can even have
8. Storm Surge
As a hurricane’s winds spiral around and around the storm, they push water into a
mound at the storm’s center. This water becomes dangerous when the storm
reaches land because it causes flooding along the coast. The water piles up,
unable to escape anywhere but on land as the storm carries it landward. A
hurricane will cause more storm surge in areas where the ocean floor slopes
9. Damage caused by Hurricanes
Hurricanes can make a lot of damage. They can wreck houses, buildings, trees,
etc. High winds are a primary cause of hurricane-inflicted loss of life and property
Hurricanes are very violent storms. I hope in my PPT you
learned about them. This project took lots of research to
make. Join me on my next PowerPoint on tornadoes.
Click here for Tornado