HURRICANES

What is a storm? Air is heated up creating low pressure Air rises Cools and condenses Air from high pressure move to low

pressure This air rises, “fueling” the storm Winds push the storm out to sea

What is a hurricane storm system low pressure center surrounding thunderstorms. Hurricanes strengthen over oceans What they are called depends on their

location of formation.Hurricane in the Atlantic oceanTropical cyclone in the Pacific and Indian oceansTyphoon in the Northwest Pacific oceanWilly Willies in Australia

How they form Begins with a thunderstorm blown out to

sea. Then it must have:

1. ocean waters must be warm to put heat and moisture into the overlying atmosphere

2. moisture from sea water evaporation must combine with that heat and energy

3. a wind pattern

hurricane takes in air from surrounding areas this new air replaces the lost old air

die out over land masses destructive force lie in their storm surges. also have some destructive force in their winds

and rains. The hurricanes spin counter clockwise in the

Northern Hemisphere and clockwise in the Southern Hemisphere**Due to coriolis effect, when rising it reverses*Winds become slower toward the poles theory

http://www.youtube.com/watch?v=kjd9Fa1H9dg

How we measure hurricanes Saffir–Simpson Hurricane Scale

Category Wind speed Storm surge

mph(km/h)(kn)

ft.(m)

Five≥ 157(≥ 252(≥ 137)

> 18(> 5.5)

Four130–156(209–251)(113–136)

13–18(4.0–5.5)

Three111–129(178–208)(96–112)

9–12(2.7–3.7)

Two96–110(154–177)(83–95)

6–8(1.8–2.4)

One74–95(118–153)(64–82)

4–5(1.2–1.5)

Additional classifications

Tropicalstorm

39–73(63–117)(35–63)

0–3(0–0.9)

Tropicaldepression

0–38(0–62)(0–34)

0(0)

A hurricane is measured using the Saffir-Simpson scale

We measure their intensity through their wind speed and storm surge height.A storm surge is the rise of water

that is associated with an incoming storm.

Their anatomy Eye- low-pressure, center of the

hurricane Eye wall- area around the eye,

includes the most violent storms Rain Bands- thunderstorm

bands that circulate out from the eye

Coriolis effect- natural phenomenon that causes winds to veer right in the northern hemisphere and left in the southern due to spin

Rain shields- completely solid or nearly solid areas of rain that are heavier the closer to the eye

Random facts After god Huracan Can release power up to the amount of

a couple of Atomic bombs Hurricane season during summer Naming

Originally only phonetic namesThen only womenChanged to alternateUsed to be named after saints

Their effect on waters Aquatic environments

Cause sediment erosion removing many habitats/homes

Salt water intrusion killing many freshwater fishFlood waters filled with many industrial products

that poison organismsFisheries can be totally destroyed by windsEffect on coastal ocean is the scraping of the

bottom due to large wavesLittle effect on open ocean due to tidal flowNormally can rebound in 3 years

Their effect on land Terrestrial environments

Wetlands destroyed the most due to the erosion or shift of barrier islands

Mangrove forests destroyed by winds, destroying many animal’s habitats

Sea grass beds, which are for feeding and nesting are often destroyed

Also causes massive damage to human structures

Examples Bhola cyclone- 1970 in Bangladesh killed

300,000 to 500,000 though only Cat. 3 Galveston hurricane- 1900 in Galveston, TX

killed 6,000 cost 500 million dollars, destroyed 3,600 Cat. 4

Hurricane Katrina- Cat. 5, 1,833 killed, costliest hurricane in U.S. history 108 billion dollars http://www.youtube.com/watch?v=s76Qn7bpCsQ

Detection/Prevention Aircrafts- fly near the hurricane to

collect information Ships- measure the heat of the sea

around the storm also collect information.

Satellites- take pictures showing the direction and speed of the storm also measure temperature and rainfall in and estimate its strength and course.

Detection/Prevention Doppler radar- show location and

intensity of precipitation and the wind motions

Levee prevent the floods from coming Reinforcing buildings help with strong

winds

Questions If I was on the southern coast of Brazil in fall

should I be worried about being hit by a hurricane?

Where are the most violent storms? How do hurricane’s destroy ocean life in the

coastal waters? What is the name of the scale we use to

measure hurricanes? Overview: http://

www.youtube.com/watch?v=75qAgSuMbzA