The document discusses tropical cyclones and their characteristics, formation, hazards, and impacts. Tropical cyclones form over warm ocean waters between 80-150 degrees north and south of the equator, fueled by ocean surface temperatures over 26.5 degrees Celsius. They are characterized by strong winds over 100 km/hr and low central pressure. Major hazards of tropical cyclones include storm surges, wind damage, and torrential rain that can cause extensive physical, economic and social impacts like structural damage, loss of life, and disruption of infrastructure and livelihoods. Responses to mitigate damage emphasize emergency action, prediction and warning systems, land use controls, floodplain management, and reducing vulnerability of infrastructure through reinforcement and building codes.

1. Variable Weather &
Changing Climate
Gateway 3

2. Extreme / Severe weather
phenomena
Tropical cyclones, droughts,
heat waves
Large scale destruction
Massive loss of life and
disruption of normalcy

3. Characteristics of
Tropical Cyclones
Strong Winds
Winds above 100km/hr
Steep pressure gradient
Low central pressure
Area of low pressure in the middle of the
cyclone

4. Where are tropical cyclones
found?
Between 8⁰ and 15⁰ north and south of
the Equator but not at the Equator.
Warm waters with Coriolis effect.
High ocean surface temperatures above
26.5⁰C need to form the cyclone.
Also known as Hurricanes and Typhoons

5. Hazards associated with tropical
cyclones
Storm surges
Wind damage
Torrential rain

6. Storm Surges
Sudden rise in sea level.
Potentially tsunami level water
levels.
Strong winds push the water
towards the coast.

7. Wind damage
Sheer wind force
Damage and destroys
infrastructure and cause injury
1992, Hurricane Andrew, USA,
reached 177 km/hr

8. Torrential rain
Large amounts of rainfall that can
result in inland flooding.
Floods leading to large
destruction of infrastructure.
Storm surges floods the area
nearest to the coast.

9. Impacts of tropical cyclones
1.Physical impacts
2.Economic impacts
3.Social impacts

10. Physical impacts
Structural damage to buildings
Massive coastal erosion leading
to loss of original shoreline

11. Economic impacts
Repair and reconstruction of damaged
property and infrastructure
Loss of crops and incidental loss of
income
Tropical Cyclone Yasi hit North
Queensland, Australia, in 2011.

12. Social impacts
Breakup of family structures –
deaths
Loss of homes
Disruptions to work and
education
Overwhelming the relief
infrastructure

14. Responses to tropical cyclones
Emergency action
Mitigation measures
Prediction and warning
Landuse control
Floodplain management

15. Emergency action
Taking immediate action to
resolve risk and danger.
Construct shelters.
Permanent community
cyclone shelters.
International aid and relief.

17. Mitigation measures
Prediction and warning
Prediction through analysis of
long-term climate records.
Patterns allow identification of
severity of damage.
Modelling of potential
movements through computer
analysis and satellite photos.

18. Mitigation measure
Land use control
Restrict the type of landuse for at
risk areas
No residential / infrastructure
Protection zone
Requires strict enforcement by
the governments.

19. Mitigation measure
Floodplain management
Planning of specific use of floodplain
areas.
Floodplains are areas near the river
mouth, highly prone to flood damage.
Analysis of the severity of past floods
and the reach.
Plan intervention / landuse to mitigate
the potential damage.

20. Mitigation measure
Reducing vulnerability of infrastructure
Reinforcing existing
infrastructures.
Buildings built to stricter
codes
Additional protection barriers
to reinforce coastline.
Seawall, Levee, etc.

21. Read the case-
study
Pg 206 to 210
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