Tropical Storms

Tropical Cyclone• Tropical cyclones are large, rotating, low-

pressure storms that form over water during summer and fall in the tropics

• The strongest of these storms in the Atlantic Ocean are known as hurricanes!

ITCZ• Intertropical Convergence Zone

Warm tropical waters near the equator…

FORMATION– Tropical cyclones require two basic

conditions to form:• An abundant supply of very warm ocean water• Some sort of disturbance to lift warm air and

keep it rising

Cyclone Movement• Tropical cyclones move according to the wind

currents that steer them.

Anatomy of Hurricane

–Once a hurricane, the development of a calm center of the storm, called an eye, takes place.

– The eyewall is a band immediately surrounding the eye that contains the strongest winds in a hurricane.

What is INSIDE?

1. A disturbance in the ITCZ zone lifts warm air near tropical waters

2. Cyclonic winds circle around a low pressure center = tropical depression

3. Wind Speeds reach 65 km/hr = Tropical Storm

4. Wind Speeds reach 120 km/hr = Hurricane

Stages of Tropical Cyclones

Saffir-Simpson Scale

• Criteria

1. Wind Speed

2. Damage Level

3. Pressure

4. Storm Surge

Running out of Energy…

• The storm moves over land and no longer has access to the warm ocean surface from which it draws its energy.

• The storm moves over colder water.

– A hurricane will last until it can no longer produce enough energy to sustain itself. This usually happens when:

Storm SurgeA storm surge occurs when hurricane-force winds drive a mound of ocean water, sometimes as high as 6 m above normal sea level, toward coastal areas where it washes over the land.

Summary

• Use the following terms in your summary!

1. ITCZ

2. Eye & Eyewall

3. Saffir-Simpson Scale

4. Storm Surge

5. “your choice”

Match the following terms with their definitions.___ tropical

depression

___ hurricane

___ eyewall

___ storm surge

A. a tropical cyclone with wind speeds of at least 65 km/h

B. the band that has the highest wind speeds in a hurricane

C. a tropical cyclone with wind speeds of at least 120 km/h

D. a mound of wind-driven water that washes over coastal lands