EASC 2310 Lesson 33: Extreme Weather - Tropical Cyclones (Hurricanes) and Floods

Flashcards about Extreme Weather - Tropical Cyclones (Hurricanes) and Floods. The flashcards are in question and answer format.

What geographical zone encompasses the regions around the Equator?

The Tropics

What latitude lines define the Tropics?

Tropic of Cancer (23.4°N) and Tropic of Capricorn

What causes areas of high and low pressure?

Ascending (rising) and descending (falling) air

What type of weather conditions does high pressure lead to?

Settled weather conditions and fair weather

What type of weather conditions does low pressure lead to?

Unsettled weather conditions and stormy weather

What is the general term for storms (cyclones) that form over warm tropical or subtropical oceans?

Tropical cyclone

What sustained wind speed must a tropical cyclone reach to be called a hurricane/typhoon/cyclone?

At least 64 knots (74 mi/hr)

Where do hurricanes occur

North Atlantic Ocean and Northeast Pacific (north of the Equator and east of the International Date Line)

Where do typhoons occur?

Northwestern Pacific Ocean (north of the Equator and west of the International Date Line)

Where do cyclones occur?

South Pacific (south of the Equator) and Indian Oceans

What is the minimum ocean temperature needed for tropical cyclones to form?

80°F (26°C) for at least the top 50 meters (~165 feet)

What is the origin of the wind that helps form hurricanes in the Atlantic Ocean?

The Trade Winds blowing westward across the Atlantic from Africa

What is the Coriolis Effect?

A phenomenon that causes fluids, like water or air, to curve as they travel across or above Earth’s surface

What is the effect of the Coriolis Effect on storm systems in the Northern Hemisphere?

Storms spin counterclockwise

What is the effect of the Coriolis Effect on storm systems in the Southern Hemisphere?

Storms spin clockwise

What level of vertical wind shear is needed for hurricane development?

Low vertical wind shear (winds that change very little going up through the atmosphere)

What is the first stage of tropical cyclone development?

Tropical disturbance

What is a tropical disturbance?

A cluster of thunderstorm clouds

At what wind speed is a storm classified as a tropical depression?

25 mph

At what wind speed does a tropical depression become a tropical storm and get a name?

39 mph

At what wind speed does a tropical storm become a hurricane/typhoon/cyclone?

74 mph

What causes hurricanes to weaken when they hit land?

They are no longer being fed by the energy from the warm ocean waters.

What are the main parts of a tropical cyclone?

Eye, Eyewall, and Rainbands

What are some characteristics of the eye of a hurricane?

Air gradually descends (sinks), precipitation ceases, and light winds

Where are the greatest wind speeds and heaviest rainfall located in a hurricane?

The eyewall

What scale is used to rank hurricanes?

Saffir-Simpson Hurricane Wind Scale

What is considered a major hurricane on the Saffir-Simpson scale?

Category 3 and higher

When is the peak of the Atlantic hurricane season?

September 10, with most activity occurring between mid-August and mid-October

What organization developed the procedures to name tropical cyclones?

The World Meteorological Organization (WMO)

When was the Atlantic Ocean hurricane-naming system developed?

1953

What is a hurricane watch?

Hurricane conditions (sustained winds of 74 mph or higher) are possible within the specified area

What is a hurricane warning?

Hurricane conditions (sustained winds of 74 mph or higher) are expected somewhere within the specified area

What weather hazard causes more deaths than any other, except heat?

Flooding

What are the two general categories of floods?

Flash floods and river floods

What are some causes of flash floods?

Slow-moving thunderstorms, thunderstorms that move repeatedly over the same area, and heavy rains from tropical storms and hurricanes

What is a floodplain?

Any land area susceptible to being inundated by floodwaters from any source