Geography: Tropical Storms

Geography: Tropical Storms

1. Causes of tropical storms

   • They start with hurricanes over the sea at a temperature of at least 27 C
     • The warm air from the sea combines with the warm air from the thunderstorm and this warm air rises
       • Due to the Earth's rotation, the storm starts to move in a spiral. The direction of the spiral depends on which hemisphere it occurs in.
         • The warm air forms clouds when it cools and condenses. The cooler air is sucked downwards as the wind speed starts to increase.
           • The tropical storm then moves over the ocean in a westerly direction because of the spin of the earth from east to west.
         • Coriolis effect
           • In the northern hemisphere the tropical storms spin in an anti-clockwise direction and in the southern hemisphere they spin in a clockwise direction.
   • Tropical storms are areas of low pressure that are surrounded by high pressure which then cause huge swirling masses of clouds

2. Effects of Tropical Storms

   • Primary Effects
     • Tropical Storm Haiyan (2013, Philippines)
       • Destroyed buildings
       • No standing structures a kilometer inland
       • Houses flattened
     • Hurricane Sandy (2012,USA)
       • Crops destroyed
       • 69 Deaths in the Caribbean
   • Secondary Effects
     • Nearly a million people without power
       • Petrol rationed
       • Spread of Cholera in flooded areas
       • Local people homeless
     • Little food, no clean water, no electricity
       • Roads Blocked
       • Deaths from drowning
       • Wide spread looting

3. Reducing the Damage of Tropical Storms

   • Forecast
     • Prepare
       • Act
         • Evacuation plans put in place
       • Education programmes to raise awareness on preparing and responding to a tropical storm, school lessons and posters can be used to spread awareness
         • In some areas buildings are designed and built to withstand tropical storms with features such as water resistant windows and windproof tiles.
           • In less developed countries they can't afford to develop buildings so they use other methods to prepare such as:
             • Educating women what to wear in case they have to swim
             • Building homes on stilts
             • Building cyclone shelters
     • Forecasts made by the National Hurricane Warning Centre (Atlantic)
       • Typhoon Warning Centre (Pacific)
       • Forecasts are available on the internet so that anyone within the cone of uncertainty can prepare for the worst
         • The speed and path of a tropical storm can be affected by many different factors so they are hard to predict

4. More tropical storms to come?

   • There is disagreement to whether the number of tropical storms is changing
     • Satellites were only used to monitor tropical storms since the 1960s so the number might have not been accurate before then
       • Natural Cycle could mean that the amount of tropical storms reduces again soon when it gets to the end of the cycle.
     • Number of tropical storms has doubled in the last 100 years
       • Global warming means the surface of the ocean have warmed up by 0.5 C
       • Since 1195 hurricanes have become more frequent and intense.
       • Short-term changes to the number of tropical storms may not be due to the actions of people