Weather and Climate KQ3 Flashcards
Characteristics of Tropical cyclones
1) Intense low pressure systems that
2) develop over warm oceans in tropics and sub-tropics
3) Sizes range in diameter from 150-1500km
4) Strong wind speeds sustained at 119km/h
5) numerous thunderstorms and heavy rainfall
Conditions and distribution of Tropical Cyclones
1) 8-20*N&S of equator, absent at equator. (Requires Coriolis effect for rotary motion)
2) Warm, still waters. High sea surface temp of 26-28c needed to fuel pressure gradient and moisture evaporation. (Over land/cooler waters, cyclones not able to sustain energy and dissipate)
3) Coriolis effect deflects winds. NH: anticlockwise, SH: clockwise
Hurricane Ike, 2008
- Storm Surges of 4-6m above normal high tide conditions
- Damages of USD$2.49 billion
Hazards associated with tropical cyclones
1) Storm Surges
2) Strong Winds
3) Torrential rain
H: Storm Surges
Def: Sudden rise of sea level in which water is piled up against a coastline beyond high-tide conditions
-Caused by combination of low air pressure and strong winds
1) Intense low pressure in the eye of the cyclone causes the sea level to rise
2) Strong winds push the waters towards the coasts, creating huge waves
- Causes floodings, destroys property and causes death
H: Strong Winds (Wind Damage)
- Strong forces of winds that accompany tropical cyclones can damage/destroy Infra and injure people
- Loose debris fly and hit people/buildings
- Affect much larger areas than storm surges
Hurricane Andrew, 1992
- Strong wind speeds of 177km/h
- Widespread damage to Bahamas and various parts of the USA
- Disrupted power supply, leaving 155,000 homes w/o electricity
H: Torrential Rains
Def: Sudden and Large amounts of rainfall
- Can last several days after cyclone, storm surges and winds have subsided
- Causes inland flooding
- Adds to river and stream waters = overflow = flooding
- Destabilize slopes when soil is saturated
- Landslides
- Affects people living at foot of hill
- Displacement and loss of lives
Hurricane Isabel, 2003
- Flooded rivers across the USA, flooding affected area 120x size of SG
- Damages >USD$2.23 billion
Impacts of Tropical Cyclones
SEAP
> Social
1) Disruption of water supply
2) Spread of diseases
3) Displacement of people
> Economic
4) Cost of damages and repair
5) Loss of income
> Agricultural
6) Food shortage
> Physical
7) Damage to infra
8) Disruption of communications (Services)
Social Impacts of Tropical cyclones
1) Disruption of water supply
- Affects sanitation and hygiene facilities
- Burst water pipes/pumps
- Limit access to safe drinking water
2) Spread of diseases
- Contaminated water supplies (water-borne diseases i.e cholera and typhoid fever)
- Stagnant pools of water = mosquitoe breeding (insect-borne diseases i.e. dengue and malaria)
3) Displacement of people
- Temporary shelters needed (Low SOL)
- Mental health of people affected
Cyclone Aila, 2009
West Bengal, India
Contaminated drinking water caused cholera outbreak, infecting 1,000 and killing 14
Hurricane Mitch, 1998
Guatemala
- Sudden increase in dengue fever and malaria cases
- Flooding and rapid disease spreading undermined healthcare efforts
- Difficult to provide adequate medical care
Economic Impacts
1) Cost of damage and repairs
- Damaged property and infra expensive to repair
2) Loss of income
- Damaged crops and halt of goods & services
Hurricane Katrina, 2005
- Destroyed 200,000 homes at east coast of USA
- Left hundreds of thousands homeless
-Damages of USD$81 million
Cyclone Yasi, 2011
- 75% banana crops in North Queensland, Australia lost
- Banana damage worth USD$350 million
- 20% sugar cane farmland demolished
Cyclone Nargis, 2008
Myanmar
USD$4 billion required to repair and provide humanitarian aid
Agricultural Impacts of tropical Cyclones
- Dependent on country
- Cyclones damage crops = no export = economic losses
- If country dependent on agricultural produce, foreign food aid required
- May result in long term food shortage
- Roads and transport infra flooded/damaged, limiting access to food
Physical impacts
- Damages to buildings and infra.
- Makes transport and accessibility to-and-within area difficult
- Food, water, medicine hard to transport, hindering recovery efforts
- Communication networks disrupted
Typhoon Ketsuna, 2009
Philipines
- Damage to roads hindered rescue work
- 80% of health centers in Manila destroyed
- Extremely difficult to distribute food and medicine
Responses to Tropical Cyclones
> Emergency Action
1) Weather warnings and advisories
2) Evacuation and cyclone shelters
3) Assistance from Govt., NGOs, international aid
> Mitigation measures
4) Prediction and warning
5) Computer modelling of cyclone
> Land Use control
6) Coastal plain management
7) Floodplain management
> Reducing vulnerability of infra.
8) Building designs
9) Coastal Dikes and River Embankments
10) Underground utility lines
EA: Weather warnings and advisories
- Give people time to make preparations to protect lives and properties (e.g. Japan)
EA: Evacuation and cyclone shelters
- Evacuating greatly reduce death and casualties
- Shelters built to with strong concrete raised above ground
- Able to withstand hazards associated with tropical cyclones
(e.g. Bangladesh)
EA: Assistance from Govt, NGOs, International aid
- Helps to repair damages (economic aid)
- Provides aid to victims (Basic necessities)
(e.g. Philipines, typhoon Megi, 2010, Philipines Red-Cross)
