1. Tropical Storms

2. Same Storm - Different Name

3. Tropical Cyclones Background:  Can be deadly! For example, in 1991 a large cyclone in Bangladesh killed >138,000 people in just two days!

4. Most widespread destructive weather hazard  For example: Hurricane Floyd (1999) only a moderate level hurricane caused US$5.6 billion in damage in the Bahamas and North Carolina (USA) and 57 fatalities Tropical Cyclones (Left) Three different cyclones spinning over the western Pacific Ocean on August 7, 2006.

5. How do cyclones form? The above figure shows how cyclones form. The green arrows show where warm air is rising. The red arrows indicate where cool air is sinking.

6. Cyclone Categories CategoryWind Speed (mph) Damage at Landfall Storm Surge (feet) 1 74-95Minimal4-5 2 96-110Moderate6-8 3 111-130Extensive9-12 4 131-155Extreme13-18 5 > 155Catastrophic19+ The Saffir-Simpson Hurricane Scale

7. Hurricane Katrina Hurricane Katrina was the most costly and most deadly hurricane in the history of the USA.  Category 5 At least 1,836 fatalities Damage estimated at US$ 81.2 billion

8. Hurricane Katrina

9. What damage is produced? Storm Surge  water that is pushed toward the shore by the force of the cyclone winds.

10. What damage is produced? Wind  responsible for the loss of power and utilities  wind damage affects larger areas than surge  flying debris  tree loss

11. What damage is produced? Flying debris  debris propelled at high speeds

12. How do we mitigate the hazard from a cyclone? Monitoring  early warning systems Infrastructure  cyclone walls  communal shelters Education and planning

13. Natural Hazards Summary Graph showing the number of deaths per year due to natural hazard events