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EXTREME WEATHER EVENTS
BOSCASTLE - FLASH FLOOD(2004) AUSTRALIA DROUGHT (2002-2010) USA-HURRICANE KATRINA (2005)
A subsequent hazard A long term condition An immediate disastrous event
-Torrential rainstorm, 60mm=fell in just 2 hours La Nina- Low pressure areas in W pacific becoming -Katrina formed over the Bahamas in August 2005, moving
CAUSE westwards; hit the Gulf Coast of Louisiana on the 25th of August
-Hot day in August(dry soil=more surface run off, less lower and high pressure in E pacific becoming higher
S infiltration) rainfall ^ over SE Asia and S Australia suffers from
2005. Although by the time Katrina made landfall it had
weakened slightly from a category 5 to a category 4 hurricane.
-Tall convectional cloudsr emnants o f Hurricane Alex drought. Increased pressure between the 2 areas TROPICAL STORMS FORMATION- Only formed when sea water is
-Steep valleys of R. Valency &R. Jordan-short lag time stronger trade winds. 27*c or higher. Warm moist air rises and condenses, move W
-Round basin-Increased river discharge-short lag time El Niño- Pressure systems, weather patterns reverse. because of the E winds near the equator. They lose strength
-Impermeable rocks & clay soil-more surface run off Warm water in E Pacific ^ up to 8'c. Warm moist air when they move over land because the energy supply from the
water is cut off. Most tropical storms happen between 5* and
-Built by sea on floodplain rises heavy rainfall over E pacific. Air circulates in 30* degrees N and S of the equator, any further N and the water
FLASH FLOOD OCCURATION- Flash floods occur within upper W air. Around N Australia the descending air isn't hot enough. The Earth's rotation deflects the path of the
a few minutes or hours of excessive rainfall, a dam or gives drier conditions than usual drought winds which causes the storms to spin.
levee failure, or sudden release of water held by an The Southern Oscillation Index- The direction, strength A tropical storm is then upgraded into Category 1 hurricane
status as maximum sustained winds increase to between 74
ice jam. Flash floods can roll boulders, tear out trees, & speed at which the changes between El Niño and
mph and 95 mph. The Saffir-Simpson Hurricane Scale is used to
destroy buildings and bridges, and scour out new normal years take place, K/A SOI. rate hurricane intensity in the Atlantic Basin.
channels. Climate Change- Maximum temp. Increasing, globally.
IMPACTS - Cars (50) and infrastructure including bridges -The allocation of irrigation water was cut to some farms -It is estimated to have cause $100 billion in
washed away - ended in sea - pollution from fuel production of irrigation crops reduced damage
leakages -Annual crops were not planted-.not enough to water to -Claimed at least 1800 lives, mostly in New Orleans
support themfarm incomes shrankfinancial strain &
- Damage to buildings and land - high insurance -N/O levee system protecting the city failed
debt farmers forced to abandon land.
claims - higher insurance premiums the following -Rural communities sufferedPpl. left towns & rural suicide pressure broke the levees in 53 places, eventually
years rate ^ flooding 80% of the city at depths of up to 6m
- 1000 residents and visitors affected -Water restrictions in all major Australian cities -Destroyed many buildings & damaged the roof of
- 58 properties flooded, 4 demolished including -Loss of vegetation & wildlife, soil erosion, declining water the Superdome, which was later used as an
visitor centre quality, increased number of bushfires & dust storms, toxic emergency centre
- 4 footbridges washed away along Valency river algal breakouts in depleted rivers, dams & lakes. -Over a million people evacuated, displaced or
-Wiped 1% off Australian economy in 2007- affecting made homeless
3 -Helicopters from RAF and Navy-To airlift people IMPORTANCE-Provides 40% of Australia's Before Katrina made landfall, the National Weather Service
P'S-PREDIC -Buildings searched-Ensure no-ones trapped agricultural produce, KA Australia's food bowl and issued hurricane watches and warnings. Accurate
TION predictions of the location time and landfall were made
PREPAREDNESS -Trees removed-Hazard if left size of France and Spain combined & home to 2
(using PAM simulation), and the evacuation of those areas
PREVENTION -Roads cleared-Improve accessibility million
most at risk was organized. A state of emergency was
-Sandbags put in place-Structural support to weak -Increase awareness and education-top down declared 2 days before Katrina made landfall & mayor of
buildings etc. -Reducing water consumption in homes-bottom up New Orleans ordered an evacuation of the city on the 28th
-£4.5 million flood defence scheme-reduce -Develop drought resistant crops e.g. Drysdale of August.
impacts if it happens again Wheat-partnership - Training and Education can help prepare future generations
-Drainage systems improved- reduce risk -Improve irrigation schemes-Drip irrigation-top and generate new prevention methods.
-Building Restrictions and Land Use planning, is easier to
-Channels widened and deepened-reduce risk down implement in MEDC's
-Banks of river reinforced-more dependable and -Use storm water efficiently-to water parks-top - Hazard prediction, allow an attempt to minimize the impact.
reduce risk. down