Climatic Hazards Flashcards
What is a climatic hazard?
A short term extreme weather event which poses a threat to people’s lives and property
What is a tropical revolving storm?
A huge storm - 300-1000km in diameter - that develops in the tropics. It is a huge swirling mass of thick cloud, with very strong wind speeds and heavy rain. The centre is known as the eye. It rotates anticlockwise in the northern hemisphere and clockwise in the southern hemisphere
What is the Saffir-Simpson scale?
The scale categorising tropical revolving storms. It starts at category 1 with wind speeds of 120-149km/h and goes up to category 5 with wind speeds over 250km/h
What are the major hazards linked to tropical revolving storms?
Strong winds cause debris to be blown around at high speeds, buildings to collapse, and trees to be blown over
Intense rainfall can cause flooding from rivers. This can cause mass movement on steep slopes
Storm surges are huge walls of sea water, up to 10m high, that can reach many kilometres inland in low lying areas. Strong winds whip up sea water and force it inland, causing storm surges
What are the primary effects of tropical storms?
Flooding can destroy crops, homes, and businesses
Death and injury caused by falling buildings, drowning, and being trapped by mass movements
Strong winds can badly damage homes, businesses, farmland, roads, rail links, and power lines
What are the secondary effects of tropical storms?
Destroyed homes cause homelessness
Mass movements and flooding can block roads, preventing aid from reaching people
Looting and breakdown of law and order
Financial hardships for governments from repairing damage
Businesses, schools, hospitals, factories, and farmland can be destroyed or damaged
Shortages of food and clean water
Where do tropical storms form and how do they behave once they have formed?
They form in the tropics over seas and oceans, once sea temperature is at least 27 degrees. They travel away from the equator: in the northern hemisphere north westerly and in the southern hemisphere south westerly. They mainly effect coastal zones, generally the easter sides of continents
What percentage of deaths from tropical storms are estimated to come from storm surges?
90%
How do tropical storms form?
Intense heating by the Sun warms the sea and air. Warm moist air begins to rise, creating a zone of very low air pressure at the surface
Water vapour in the rising air condenses to form huge towering clouds and rain begins to form
Air from surrounding zones of high pressure moves towards the zone of low pressure, creating powerful winds
At the centre air gently sinks and the weather is calm - the eye
What were the primary impacts of Hurricane Katrina (2005) on New Orleans?
1800 deaths, mostly from drowning 300,000 homeless 80% of the city flooded from the storm surge and overflowing rivers 3 million without power Oil spills of >7m gallons
What were the secondary impacts of Hurricane Katrina (2005) on New Orleans?
Breakdown in law and order - looting of abandoned properties
Hundreds of thousands in need of shelter, food, clean water, and medical services
Risk of diseases like cholera breaking out
Estimated $125bn cost to the US economy
Why did Hurricane Katrina have such an impact on New Orleans?
The city is built on low lying, flat land, near where the Mississippi river enters the Gulf of Mexico, directly where the Cat 4 Katrina hit
The city’s coastal protection and river flooding protection schemes were not strong enough to cope with the storm surge and intense rainfall
How did people and New Orleans authorities attempt to reduce the impact of Hurricane Katrina?
Prediction - the hurricane’s path was predicted and people were ordered to evacuate 2-3 days before the hurricane hit - 80% of people did
Preparation - people reinforced homes by boarding up windows and putting sand bags against doors. Emergency shelters were set up in the main sports stadium, where food, water, and aid was stockpiled
Protection - levees had been built along the coastline and some riverbanks
What were the immediate and long term responses to Hurricane Katrina?
A major search and rescue operation was launched, checking for survivors. Emergency medical care, water, food, and shelter were provided at the sports stadium (Louisiana Superdome). The National Guard were brought in to assist with this and establish law and order.
A massive rebuilding programme was launched, though this was not completed over 5 years after the storm. New stronger sea defences were built.
How does the USA now monitor and predict hurricanes?
Satellites and aeroplanes monitor sea temperature, cloud height, and precipitation, among other things that could indicate a hurricane forming. This data is fed into computers which predict the chance of a hurricane and its path, so evacuation warnings can be issued.
