1. Hurricanes
Chapter 13.3

2. Objectives The conditions required for tropical cyclone development
The life cycle of a tropical cyclone
The dangers of tropical cyclones

3. Cyclone
Tropical cyclone
Large, rotating, LOW pressure tropical storm

4. A.K.A
Tropical Cyclones have different names depending on where they form
Pacific Ocean: Typhoon
Indian Ocean: Cyclone
Atlantic Ocean: Hurricane

5. Requirements for Cyclone Formation
1. Abundant supply of warm ocean water
2. Mechanism to lift the warm air
3. Minimum wind shear

7. 1st stage of formation Formative stage – moving tropical disturbance
Less dense, moist air rises
Rainfall and air circulation
As air moves to replace low pressure area, coriolis effect takes place
Produces a counter-clockwise rotation of the air
Known as tropical depression (less than 38 mph)

9. 2nd stage of formation Mature stage
moving air approaches center, more condensation
more energy
Air pressure in center continues to drop
Wind speed increases
39 to 73 mph
Tropical storm

11. Mature stage
When a tropical storm intensifies with winds greater than 73 mph it becomes a hurricane
Eye
Center of storm
Calm and sunny
Eyewall: surrounds the eye
Strong winds and dense clouds on the edge of the eye

13. 3rd stage of formation Dissipation stage Moved over land – friction
Moved over cold water
No longer has warm air at the surface to feed it

18. Tropical cyclone movement
Move according to wind currents which steer them
Caught up in the high pressure systems that are present in the tropics
Move west and become caught up in the westerlies
React with mid-latitude systems
Interaction with many systems make their path unpredictable

19. Saffir-Simpson Hurricane Scale

20. Hurricane hazards Damage Mostly caused by high winds Storm surge
Hurricane force winds carry a mound of ocean water toward shore