Tropical Storms - Assossiated Hazards Flashcards
Why are strong winds dangerous? What is a strong wind?
- Average wind speeds: 75mph
- Tear roofs, break windows, damage communication
- Debris = flying missiles
- Power cuts and fires from damaged power lines
What happens to the tide when a tropical storm occurs?
It raises - this is due to low atmospheric pressure
(AKA vertical sea rising)
Why is storm surge so dangerous? How is it caused?
- Floods low-lying areas
- Loss of life
- Destroys agriculture with salt contamination and debris
- Pollutes fresh water
- Increases coastal erosion
- Caused my intense low atmospheric pressure (vertical sea rise) and surface winds
How high was Hurricane Katrina’s storm surge?
7.6m
Why are a large number of people vulnerable to tropical storms?
They are most powerful at landfall - historically, many settlements are coastal (trade). Most of the world’s major cities are on the coast (London, Mumbai)
Why is coastal/river flooding so dangerous? What causes it? What is an example of a detrimental flood?
- Flash floods in urban areas overwhelms drains and impermeable surfaces exacerbate this
- Hurricane Irene (2011, New Jersey) evacuated 1 million people: the flood coated $1B
- Humid air = rain (often 200mm+ in hours)
- River basins are overwhelmed
How can we adapt to tropical storms? Is this approach realistic universally?
- Land-use zoning reduces coastal/river catchment vulnerability (figure out where low value land is)
- Storm surge elevation marks: helpful when land zoning
- Stilts
- This approach is the most realistic for many (it helps if land use zoning is done before buildings are erected)
How can we use prevention tactics to lighten the impact of tropical storms?
- Forecast
- Sea walls, river flood defenses (perhaps expensive)
- Insurance (not universal)
- Evacuation routes (the more local the scale, the better)
What is an example of a place adapting to hurricane implications? Was it successful?
Bangladesh, following the Bhola cyclone (1970). This killed half a million.
- Warning system up levelled - wardens spread warnings in remote areas
- Concrete cyclone shelters on stilts (new place of universal refuge)
A similarly intense cyclone in 2003 killed 3000 (reduced impact - success?)
How can we use preparedness strategies to reduce the implications of tropical storms?
- Posters, radio, TV (campaigns)
- Minor structural improvements on infrastructure (windows)
- Personal evacuation plans/emergency kit
- Insuring all properties
How is Florida prepared for tropical storms?
- Signposts indicating evacuation routes and shelters
- Hurricane watch and warning system
- SLOSH places storm surge prediction cones in Miami
How can we mitigate the implications of tropical storms on low-lying areas?
- Structural intervention, disaster aid, insurance
- Soft engineering: trees, beaches, mangroves
- Hard engineering: sea walls
How is South Carolina helping insurance issues?
South Carolina Department of Insurance: grants for home owners to make infrastructure resilient
Why do issues with insurance impact the individual’s perception of hurricanes?
Behavioural responses may be influenced by potential economic loss
What may disaster aid include? What triggers it?
- Immediate humanitarian relief
- Long term loans to reconstruct
- Deploying expert personnel (doctors, rescue teams)
- Triggered by declaring a state of emergency - federal/state support. Armed forces. NGOs.
Why is insurance encouraged? What are the disparities? What is an example of uneven insurance?
- People in hurricane prone areas in the US are encouraged to take out insurance against wind damage and follow building regulations
- Wealthier people can afford premiums - uneven
- The New Orleans deprived population had no insurance - they refused to be evacuated because of this (save property)
What is an example of a state using mitigation strategies against tropical storms?
Galveston, Texas: 5m high sea wall built - spreads 5km.
Built after the 1900 storm surge killed 12,000
Why is New Orleans vulnerable?
Flooding risk - Mississippi river
Mississippi delta wetlands have been drained - starved of sediment
New Orleans is sinking (built on drained soft sediment) - compaction
Levees only designed to stand a category 3 storm - not acted upon. Industrial canal and 17th Street canal failed - mapped deaths correlated
