3.1 Tropical storms Flashcards
What is a tropical storm
Intense, low pressure weather systems which develop in the tropics
What are the requirements needed for a tropical storm to form
- Ocean depth at least 70m
- Ocean temp at least 27c
- low altitude wind
How exactly does a tropical storm form
- Warm air develops above the ocean, warm air expands and rises, as this air rises, more wind comes in to replace it.
- The rising air contains moisture which condenses to form clouds. This creates a draft draws even more warm air
- The condensation releases LATENT HEAT ENERGY, proving it with a positive feedback cycle of heat (more power)
- The CORIOLIS effect makes rising currents spiral around the storm centre, making the storm mature
What are the different parts of a tropical storm
Eye of the storm (calm)
Eye wall (most damaging)
Beyond this, a similar, smaller pattern expands
Where are most tropical storms distributed
5 and 20 degrees north and south of equator, moving westwards
They usually last 1-2 weeks and around 100 occur every year
1/3 Occur in South east Asia
1/5 Occur in Australia
What scale do we use to measure the magnitude of tropical storms
The Saffir-Simpson scale has 5 levels based on
1.central pressure
2. wind speed
3. damage potential
What are the primary physical impacts of a tropical storm
- Storm surge (most deaths)
- Strong winds
- Heavy rainfall and flooding
What are the secondary physical impacts of a tropical storm
- Mudslides
What is a storm surge and how are they formed
Surges of high water that sweep inland from the sea, and flood low lying areas
They are caused by intense low pressure, causing the sea to rise and are driven by low surface winds. One of the highest ever recorded was Hurricane Katrina (8.5m high)
What are some methods we can use to predict cyclones
- Geostationary satellites (watch hurricanes as they from)
- Weather Aircraft (measure air pressure and wind speed)
Why is it hard to predict hurricanes
They follow an erratic path and even with constant surveillance , 18 hours is the most notice given
What are some methods we can use to prevent yclones
Cloud seeding - force cyclones to release water over the sea to have less energy, but this will effect the global energy system
What are some methods we can use to plan for cyclones
- Practice Evacuation
- Educate people
- Land-Use planning
- Retrofitting
- LOCAL COMMUNTIY PLANS
What are 2 case studies to look at for tropical storms
Hurricane Katrina
Cyclone Nargis
Give some background context for Hurricane Katrina
Developed August 2005 near the Bahamas
6 days later it hit Mississippi and Louisiana
What were the primary physical effects of Hurricane Katrina
280kmh wind
10m high storm surge
What were the primary human effects of Hurricane Katrina
$200 billion in damages
18,000 dead
1 million refugees
Area size of UK left without power and water
80% of New Orleans flooded and looted
Devastated animal breeding grounds
What were the secondary human effects of Hurricane Katrina
Every state has a Katrina refugee
12,000 people still in temporary trailers years later
Black Americans suffered most
What were the primary responses for Hurricane Katrina
33,000 people saved by the Coastguard
Emergency supplies sent out
Temporary housing
What were the secondary responses for Hurricane Katrina
$62.3 billion in aid
Damaged properties quickly repaired
What was the main downfall of Hurricane Katrina
Inadequate planning and communication
Give some background context for Cyclone Nargis
Developed April 2005 near the Bay of Bengal
Change in wind made it hit BURMA, MYANMAR as a category 4
What were the primary physical effects of Cyclone Nargis
215kmh wind
600mm of rain
4m Storm surge
What were the primary human effects of Cyclone Nargis
$10 billion in damages
135,000 deaths
95% of all low land homes destroyed
5 million homeless
600,000 hectares of farmland damaged
What were the secondary human effects of Cyclone Nargis
No adequate food or water
Years later, people still living in wrecked villages
What were the primary responses for Cyclone Nargis
Local communities carried out search and rescue
Aid was not allowed into the country due to fear of invasion. Finally, aid was accepted and it was slow due to the destroyed infrastructure
What were the secondary responses for Cyclone Nargis
Very slow improvements
Government were too overwhelmed
What was the main downfall of Cyclone Nargis
Inadequate planning by government
Lack of information given to aid organisation
