AQA Geography - Storm and Wildfire Hazards

What is a tropical storm?
a large rotating storm around a centre of very low pressure. Most systems have a diameter of about 650 km, less than half that of a mid-latitude depression. Wind speeds often exceed 120kph
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Why are the clouds so high?
The huge amount of heat required to create and maintain a tropical cyclone is reflected by the height of the clouds near its centre, often up to 12km above the surface.
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Conditions required for tropical storms
27 degrees sea surface temperature ocean depth of 70m Located between 5 and 20 degrees north and south of the equator Between tropics of cancer and capricorn
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What does the air need to be like for the storm to occur?
Allows Coriolis Force to rotate the air Low level convergence of air in the lower atmosphere circulation system Rapid outflow of air in the upper atmosphere
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What is the development of a tropical storm?
Move westward due to Earth's rotation - 15-30km/h Continue to grow as condensation releases heat energy picks up warmth from the sea Break up over land (friction and little moisture) or as they move out of tropics 35'N/S as sea gets cooler
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Characteristics of the storms
Central clear 'eye' of descending air Around eye, massive cloud walls with rapid uplift 12km high, 200-500km in diameter High volume rainfall - up to 500mm in 24hrs Very low air pressure- 900mb Eye wall dominated by intense thunderstorms
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Impacts of the storm
Wind, storm surge, intense high rainfall, lightning
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Primary impacts
homes destroyed, deaths and injuries from flying debris
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Secondary impacts
flooding, pollution (sewage/drains etc), disease, hunger, fires (power lines down), transport disrupted
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Tertiary impacts
long-term economic impacts (e.g. cost, destruction of infrastructure, loss of jobs,etc)
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Environmental impacts of Tropical storms
elief- landslides, mudflows Drainage- waterlogging, floods Vegetation- trees destroyed/uprooted, habitats destroyed Pollution of water supplies, disease
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Social impacts of Tropical storms
Health- injuries and death, disease, depression Housing- destroyed, temporary shelter, forced to migrate Social unrest- looting, family break up, tension
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Economic impacts of Tropical storms
Infrastructure- destroyed (e.g. roads, power, schools) Agriculture- cash and food crops lost, pollution, tree crops hit hard Transport- bridges destroyed, road and rail damage, loss of aeroplanes Trade- loss of exports, need to import, cost of aid
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What measures the strength of tropical storms?
Saffir-Simpson scale:
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What is a storm surge?
Increase in sea level by about 3 meters in height that sweeps inland flooding low-lying areas
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What causes a storm surge?
Combination of intense low atmospheric pressure of tropical storm with powerful driving surface winds
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What threat do storm surge pose?
extensive serious flooding, loss of life, inundate agricultural land with salt water and debris as well as pPolluting fresh water supplies, destroy houses and infrastructure
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Name of tropical storm which included a storm surge
Hurricane Katrina, USA, surge up to 7.6m
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Hurricane katrina protection
Proved very good but US National Oceanic and Atmospheric Administration (NOAA) is improving it by adding more weather buoys in the Gulf of Mexico
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Katrina death toll and injured toll
1836 people killed -300,000 houses destroyed -hundreds of people homeless
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social impacts
3 million without electricity -main route out of New orleans closed, 1-10 bridge collapsed -polluted water supplies-sewage, chemicals, dead bodies- 5 people died from bacterial infections -schools damaged/destroyed, 18 schools in New Orleans destr
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Econmic impacts
230,000 jobs lost-buisnesses destroyed -cost of damage-$300 billion -30 oil platforms in Gulf of Mexico damaged/destroyed -5300km of forest destroyed-Mississippi, affected logging industry-$5 billion -ports damaged-disrupted shipping industry
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Environmental Impacts
Coastal habitats damaged-sea turtle breeding beach -flooding damaged oil refineries-Louisiana, oil spills -flooding of salt marshes in Louisiana-loss of habitat
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REsponses after the event
-100,000 didn't evacuate, as they wanyed to protect ther property or didn't have enough money/transport -emergency shelters set up for people -Louisiana superdome sheltered 26,000people -coastguard, police, fire services, army rescued over 50,000
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some emergency shelters weren't properly prepared -enough food to feed 15,000 at superdome for 3 days, 26,000 turned up - widespread looting-lack of police/troops
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Background on the Philippines
The Philippines consists of a group of islands in the South China Sea. The country regularly suffers from large typhoons that move in from the south west every year during the tropical storm season.
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The typhoon's Formation
The storm tracked north-west towards South East Asia. It developed into a super typhoon just before it made landfall in the Philippines on Friday 8th November 2013, as a category five equivalent typhoon. It then continued across the South China Sea t
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Effects of the typhoon
11.5 million people were affected by Typhoon Haiyan. Over 10,000 people lost their lives. 600,000 people were displaced. 130,074 houses were destroyed. The Philippine government estimated that about 175,000 acres of farmland were affected.
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Typhoon Haiyan death toll etc
t killed approximately 7400 people (6,340 confirmed, 1,061 missing) and affected 9 million people.
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Economic impacts
estimated losses at $2.9billion with much of this in agriculture. The major rice and sugar producing areas for the Philippines were destroyed. A total of 131,611 tons of rice was lost , together with much of the coconut crop.
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What happened to the airport?
Tacloban airport terminal building was also completely destroyed by a 5m storm surge.
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Social Impacts
they became refugees in lass affected areas and migrated there.
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How did it effect the fishing/fishermen?
fishing communities were affected with the storm destroying boats and associated equipment.
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Environmental impacts
The natural environment was also affected, with loss of forests, trees and widespread flooding. Local ecosystems were also affected by sewage leaking from overwhelmed sewage systems and oil leaks. A lack of sanitation = pollution
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What caused the typhoon?
Deep ocean water above 27°C in temperature. Warm, moist air that after rising, cooled and condensed to produce a band of especially heavy rain.
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Immediate responses
Internationsl government and aid agencies respnded quickly with food aid, water and temporary shelters US aircraft carries and helicopters assited with search and rescue and the delivery aid. UK government sent shelter kits
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Long term responses
The UN and countired including the UK, Austrailia, Japan and the US donated financial ain, supplies and medical support. Rebuilding of roads, bridges and aiport facilities. 'Cash for work' prorammes - people paid to help clear debris and rebuild it
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Primary impacts
6300 people were killed. Most drowned from the 5m high storm surge. Over 600,000 people were displaced and 40,000 homes were destroyed or damaged. 90% of the city of Tacloban was destroyed and left in ruin. Tacloban airport was badly damaged.
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Secondary impact
14 million people affected, many left homeless. 6 million people lost their source of income. Flooding caused landslides and blocked roads, cutting off aid to remote communities. Power supplies in some areas cut off for a month.
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Causes of Wildfires
Can be ignited by a human or natural cause Quasi-natural: when a normally benign natural condition or natural process is made more disastrous by human activity
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Slash and burn
Controlled fires that are used to clear land
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Nature of Wildfires
Travel faster on sloped ground Convection currents and strong winds can ignite isolated spot fires Burning fragments of vegetation (firebrands) can roll downhill due to gravity and start other fires
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Rural hazard Occur on the boundary of substantial settlements Areas with dry seasons Parts of Australia, USA, Canada, Southern Europe
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why is there a need for wildfires?
Fire can clear vegetation aid seed germination stimulate the growth of certain plants Get rid of insects and parasites Some plants e.g. banksia need fire for their woody fruit to open and regenerate
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Other cards in this set

Card 2


Why are the clouds so high?


The huge amount of heat required to create and maintain a tropical cyclone is reflected by the height of the clouds near its centre, often up to 12km above the surface.

Card 3


Conditions required for tropical storms


Preview of the front of card 3

Card 4


What does the air need to be like for the storm to occur?


Preview of the front of card 4

Card 5


What is the development of a tropical storm?


Preview of the front of card 5
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