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Flashcards in Storm Hazards Deck (10)
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How do Tropical Storms Form?

Tropical storms develop over warm sea water that is over 27°c to at least 50 meters below the sea level, this allows lots of water to evaporate rapidly, if this takes place in a location that is above 27° and over 5° either side of the equator the CORIOLOS EFFECT of the earths rotation may be enough to deflect the path of the wind and being a spinning motion, they always move away from the equator due to the Coriolis effect and almost always move westwards due to Easterly trade winds, tropical storms loose their supply of warm most air over land so their energy is cut off, they are circular on shape and spin anti-clockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere.


How can we measure tropical storms?

The Saffir-Simpson scale uses wind speed to categories storms into 5 groups, 1 is the weakest with sustained winds of only around 120km and catagory 5 is the strongest with sustained winds of around 250km per hour.


What is an example of a Hurricane in a HIC? And when did it happen?

Hurricane Katrina struck the South East USA on the 29th of August 2005.


What are some facts about Katrina?

> It formed over the Bahamas on the 23rd and slowly strengthened and when it struck Louisiana and Mississippi on the 29th it was a category 3 hurricane.

> It brought winds of around 200 km per hour and 200mm of rainfall to Louisiana and a storm surge of 8.5 meters in Mississippi.


What were some of the impacts of the storm?


+ 1836 people were killed.
+ 300,000 homes were destroyed.
The I-10 bridge into New Orleans collapsed leaving the city which was 80% submerged totally isolated.
+ Water supplies were polluted with sewage and industrial chemicals, 5 people died from drinking contaminated water
+ 18 schools were destroyed.

+ 230,000 jobs lost from damaged businesses.
+ 30 oil platforms on the Gulf of Mexico were destroyed as was the major port of Gulfport Mississippi.
+ 5,300 km of forest was destroyed, resulting in a loss of around 5 billion dollars in lost logging revenue.
+ Up until Hurricane Harvey, Katrina was the USAs most expensive disaster costing $300 billion.

+ Coastal habitats were destroyed including turtle breeding beaches.
+ Coastal conservation areas were also destroyed such as Breton national wildlife reserve.
+ Flooding of salt marshes lead to habitat loss.
+ Damaged oil refineries leaked oil, causing oil spills.


How was the recovery after Katrina?

> Effective warning systems helped the USA respond rapidly.

> The National Hurricane Center issued multiple hurricane warnings for the effected area and consistently tracked every feature of the storm.

> Some areas such as New Orleans made mandatory evacuations, it’s estimated that 80% of NOs population evacuated.

> The USAs FEMA mobilised quickly to mitigate against the flood.

> Emergency shelters such as the Louisiana Superdome helped shelter 26,000 people during the hurricane.

> The emergency services helped rescue 50,000 people alone.

> Charities collected over 4 billion to help provide aid.


What is an example of a tropical storm event in an LIC and when did it happen?

Cyclone Nargis struck Myanmar on the 2nd of May 2008.


What are some facts about Cyclone Nargis?

> The storm had formed in the Bay of Bengal in the late week of April 2008.

> As it approached the coast of Myanmar (One of the least developed nations on earth) it strengthened to a category 4 cyclone.

> It hit on May 2nd with wind speeds up to 215km/h and a storm surge of 5 meters.


What were some of the impacts of Nargis?


> The cyclone hit the Irrawaddy delta head on, the area which lies majority below 1 meter above sea level was flooded.


> More than 140,000 people were killed
> 450,000 homes were destroyed.
> 4000 schools and 75% of health facilities were destroyed.
> 43% of freshwater ponds were contaminated leaving over 70% of residents without clean water.
> Disease became a major issue as Dysentery spread rapidly, killing many.


> Over 6000km2 of agricultural land (primarily Rice Paddies) was damaged.

> Huge amounts of crops and animals were lost and 40% of food storage was destroyed.

> With the destruction of many fishing boats, millions lost their livelihoods.

> The total cost was around $4 billion.


> 380km2 of Mangrove forest was lost, making many future flooding events worse.
> Flooding caused extensive erosion and salinisation.


What were the responses to Nargis?


> Indian Meteorologicalists had warned the government of Myanmar of the oncoming storm as the nation didn’t have a service of their own, despite this the government took no precautions with no emergency warning system and no evacuation plans.

> After the storm the military dictatorship that ruled Myanmar refused any foreign aid or aid workers but on the 9th of May loosened restrictions and the residents were given tents and food etc. By the UN refugee agency, the delay greatly increased the number of deaths and long-term impact.