Hurricanes & TyphoonsHurricanes & Typhoons

By: Momina & VanessaBy: Momina & Vanessa

What is a Hurricane?What is a Hurricane?

• A hurricane is a large, spinning wind A hurricane is a large, spinning wind system that develops over warm system that develops over warm seas near the equatorseas near the equator

• Hurricanes are technically tropical Hurricanes are technically tropical revolving stormsrevolving storms

• They are characterized by rotating They are characterized by rotating winds that have the speed of about winds that have the speed of about 75 mph75 mph

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• The tropics mostly have the most extreme The tropics mostly have the most extreme weather conditionsweather conditions

• The air heated by the sun rises swiftly The air heated by the sun rises swiftly which creates areas of very low pressure, which creates areas of very low pressure, the warm air rises then it becomes loaded the warm air rises then it becomes loaded with moisturewith moisture

• It creates into a massive thunder cloudIt creates into a massive thunder cloud

• It can be formed into a huge circle that It can be formed into a huge circle that can be up to 1,200 miles acrosscan be up to 1,200 miles across

A Hurricane BeginsA Hurricane Begins

• Hurricanes usually begin in the steamy, late summer in the Hurricanes usually begin in the steamy, late summer in the tropics, when the seas are the warmesttropics, when the seas are the warmest

• For the hurricanes to develop, the sea surface temperature has For the hurricanes to develop, the sea surface temperature has to be at least 78 degrees Fahrenheit to be at least 78 degrees Fahrenheit

• When the warm air rises from the seas and condenses into When the warm air rises from the seas and condenses into cloudsclouds

• The result of this mixture of heat and moisture is often a The result of this mixture of heat and moisture is often a collection of thunderstorms, from which a tropical storm can collection of thunderstorms, from which a tropical storm can developdevelop

• During the hurricane season, the coriolis effect of the earth’s During the hurricane season, the coriolis effect of the earth’s rotation starts the winds in the thunderstorm spinning in a rotation starts the winds in the thunderstorm spinning in a circular motioncircular motion

• At the center of the storm is a calm, often cloudless area called At the center of the storm is a calm, often cloudless area called the eye, where there is no rain, and the winds are fairly lightthe eye, where there is no rain, and the winds are fairly light

The BuildupThe Buildup

• As the hurricane builds up it begins As the hurricane builds up it begins to moveto move

• It is sustained by a steady flow of It is sustained by a steady flow of warm, moist airwarm, moist air

• The strongest winds and heaviest The strongest winds and heaviest rains are found in the towering rains are found in the towering clouds which merge into a wall about clouds which merge into a wall about 12-18 miles from the storm’s center12-18 miles from the storm’s center

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• Winds around the eye can reach speeds of Winds around the eye can reach speeds of up to 125 mph and a fully developed up to 125 mph and a fully developed hurricane pumps out about two million hurricane pumps out about two million tons of air per second tons of air per second

• The hurricane travels at speeds of The hurricane travels at speeds of between 10 &30 mphbetween 10 &30 mph

• When it hits an area of cold sea or land, it When it hits an area of cold sea or land, it enters a cold, inhospitable climate, where enters a cold, inhospitable climate, where its supply of moist air is cut offits supply of moist air is cut off

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• The eye quickly disappears and the storm The eye quickly disappears and the storm begins to die downbegins to die down

• Yet it is when it hits the land that a Yet it is when it hits the land that a hurricane, typhoon, or cyclone causes hurricane, typhoon, or cyclone causes most damagemost damage

• 90% of victims are claimed when the 90% of victims are claimed when the storm first smashes ashore, bringing with storm first smashes ashore, bringing with it not only powerful winds, but huge waves it not only powerful winds, but huge waves called storm surgescalled storm surges

The Storm SurgeThe Storm Surge

• The deadly companion of every tropical storm The deadly companion of every tropical storm is the storm surge; the huge mounds of is the storm surge; the huge mounds of seawater that are whipped up by the powerful seawater that are whipped up by the powerful windswinds

• The first sign is a storm surge can occur The first sign is a storm surge can occur nearly a week before the actual hurricane, nearly a week before the actual hurricane, typhoon, or cyclonetyphoon, or cyclone

• Winds move outward much faster than the Winds move outward much faster than the storm itself and whip up the sea into waves up storm itself and whip up the sea into waves up to 5 ft. high along the costlineto 5 ft. high along the costline

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• When the storm is about 110 mi. from When the storm is about 110 mi. from land, huge waves driven by its winds begin land, huge waves driven by its winds begin to crash ashoreto crash ashore

• The deafening roar of the surf can be The deafening roar of the surf can be heard miles inlandheard miles inland

• This is followed by the most deadly and This is followed by the most deadly and destructive element of the surge as the destructive element of the surge as the huge bulge of water that forms beneath huge bulge of water that forms beneath the storm’s eye smashes ashorethe storm’s eye smashes ashore

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• Low-lying coastal areas can be Low-lying coastal areas can be devastated by the severe floods that devastated by the severe floods that result, and many lives and homes are result, and many lives and homes are often lostoften lost

The DamageThe Damage

• For anyone caught in a hurricane, the For anyone caught in a hurricane, the experience is a terrifying one. experience is a terrifying one.

• Fierce, whirling winds rip across the Fierce, whirling winds rip across the countryside, overturning cars and countryside, overturning cars and heavy trucksheavy trucks

• Trees are ripped from the ground, Trees are ripped from the ground, and whole buildings can be lifted and whole buildings can be lifted from their foundationsfrom their foundations

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• Some of the worst disasters occur near Some of the worst disasters occur near coastal areas, where stormy seas coastal areas, where stormy seas contribute to the havoc that is wreakedcontribute to the havoc that is wreaked

• In 1938, one of the most powerful In 1938, one of the most powerful hurricanes in history swept through Long hurricanes in history swept through Long Island, New YorkIsland, New York

• In just seven hours, the storm killed at In just seven hours, the storm killed at least 600 people and destroyed the homes least 600 people and destroyed the homes of over 60,000of over 60,000

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• The total damage was estimated at The total damage was estimated at the enormous sum of one-third of the enormous sum of one-third of one billion dollarsone billion dollars

• The storm destroyed26,000 cars and The storm destroyed26,000 cars and 29,000 miles of electric, telegraph, 29,000 miles of electric, telegraph, and telephone wires and flooded and telephone wires and flooded thousands of acres of landthousands of acres of land

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• One coastal area on the island was One coastal area on the island was so badly it hit by the hurricane that so badly it hit by the hurricane that 200 homes there were completely 200 homes there were completely swept awayswept away

• Rescue workers searching for Rescue workers searching for missing people had to use maps from missing people had to use maps from telephone companies to identify the telephone companies to identify the sites on which the houses once stoodsites on which the houses once stood

Are We Causing More?Are We Causing More?

• Hurricanes are sustained by warm, Hurricanes are sustained by warm, moist airmoist air

• The countries of northern Europe The countries of northern Europe have a fairly cool climatehave a fairly cool climate

• So why have they been hit by So why have they been hit by hurricanes in recent yearshurricanes in recent years

• One theory is that global warming is One theory is that global warming is having some effecthaving some effect

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• As the planet heats up, more parts of As the planet heats up, more parts of the world are developing the kind of the world are developing the kind of climate that is ideal for tropical climate that is ideal for tropical stormsstorms

• The gases in earth’s atmosphere act The gases in earth’s atmosphere act like the glass of a greenhouse, like the glass of a greenhouse, trapping enough heat from the sun to trapping enough heat from the sun to keep the planet warm enough for lifekeep the planet warm enough for life

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This is known as the This is known as the “Greenhouse Effect”.“Greenhouse Effect”.One of the main greenhouse One of the main greenhouse gases is carbon dioxide.gases is carbon dioxide.Other greenhouse gases are Other greenhouse gases are methane, water, vapor, and methane, water, vapor, and chlorofluocarbons.chlorofluocarbons.The only way we can prevent The only way we can prevent global warming is by global warming is by controlling the amounts of controlling the amounts of theses gases that are theses gases that are released into the atmosphere.released into the atmosphere.