HurricanesHurricanes

What are Hurricanes?What are Hurricanes?•Hurricanes Hurricanes

are intense are intense tropical tropical cyclones with cyclones with a maximum a maximum speed of at speed of at 65 knots 65 knots (74mph).(74mph).

By Any Other NameBy Any Other NameIn the Eastern Pacific they In the Eastern Pacific they are called are called typhoons.typhoons.In the Indian Ocean they’re In the Indian Ocean they’re called called cyclones.cyclones.

How are they formed?How are they formed?Hurricanes gather

heat and energy through contact with warm ocean waters. Evaporation from the seawater increases their power.

Hurricanes rotate in a counter-clockwise direction around an "eye" in the Northern Hemisphere and clockwise direction in the Southern Hemisphere.

Physical Make-upPhysical Make-up

•Hurricanes Hurricanes have a have a diameter of diameter of less than less than 100 miles to 100 miles to over 500 over 500 miles.miles.

When does hurricane season start?

The Atlantic hurricane season is from June 1 to November 3.0

Hurricane PowerHurricane Power•Hurricanes Hurricanes are ranked are ranked on a 1-5 on a 1-5 scale called scale called the Saffir-the Saffir-Simpson Simpson Scale.Scale.

Hurricane PowerHurricane Power•A 1 would be A 1 would be

a minimal a minimal hurricane hurricane with winds with winds 74-95 mph.74-95 mph.

•A 5 is A 5 is catastrophic catastrophic with winds with winds 155 mph+155 mph+

Danger from Danger from HurricanesHurricanes

•In the US, In the US, most people most people that die from that die from hurricanes hurricanes are killed by are killed by fresh water fresh water flooding. flooding.

Danger from Danger from HurricanesHurricanes

•WorldwideWorldwide, most die , most die from the from the storm storm surge.surge.

Storm SurgeStorm Surge•To Answer that question To Answer that question let’s take a look at storm let’s take a look at storm

surge.surge.

THE WIND!THE WIND!

•Flying Flying objects in objects in the wind the wind can be very can be very dangerous. dangerous.

THE WIND!THE WIND!•Take a look Take a look at this piece at this piece of wood that of wood that was driven was driven into the into the palm tree.palm tree.

Some historical Some historical hurricaneshurricanes

•Hurricane Hurricane Kenna-Kenna-

20022002•Katrina-Katrina-20052005•Ernesto-Ernesto-20122012

Tornadoes.

What is a tornado?A tornado is a

violent rotating column of air extending from a thunderstorm to the ground

Tornadoes powerThe most violent

tornadoes can cause a tremendous destruction with wind speeds of up to 300 mph.

Tornadoes power They can

destroy large buildings, uproot trees and hurl vehicles hundreds of yards.

How do tornadoes form?Most tornadoes form

from thunderstorms. You need warm, moist air from the Gulf of Mexico and cool, dry air from Canada. When these two air masses meet, they create instability in the atmosphere.

What do tornadoes look like?Tornadoes can

appear as a traditional funnel shape, or in a slender rope-like form.

When are tornadoes most likely to occur?Tornadoes can

happen at any time of the year and at any time of the day.

Volcanoes

What is a ?A volcano is a mountain that forms when magma reaches the surface of the Earth.

Magma rises because it is less dense than the solid rock around it.

What causes volcanoes? Tectonic Plate Boundaries

A volcano erupts when magma and gases find a way to escape, so they burst to the surface through a vent. An eruption can be quite gentle or very violent.

Types of volcanoVolcanoes can be active, dormant or extinct.

• A volcano is active, or alive, when it erupts often.

• When a volcano is dormant, or sleeping, it has not erupted for a long time – but it might in the future.

• A volcano is extinct, or dead, when it hasn’t erupted for at least 100,000 years.

Parts of volcanoesCrater – a deep hollow at the

top of a volcano.

Lava – melted rock that flows down the volcano.

Magma – melted rock inside the Earth.

Vent – a crack on the side of a volcano where magma can escape

Volcanic Effects

• Pyroclastic flow• Lahars/Mud flows• Pyroclastic fall• Lava flow• Noxious Gas• Earthquakes

Volcanic Fatalities

• 92,000 Tambora, Indonesia 1815.

• 36,000 Krakatau, Indonesia 1883.

• 29,000 Mt Pelee, Martinique 1902.

• 15,000 Mt Unzen, Japan 1792.

Pyroclastic Flow• For example,

eruption of Vesuvius in 79 AD destroyed the city of Pompeii.