Climatic Hazards Flashcards
(40 cards)
What’s a cyclone?
A system of winds rotating inwards to an area of low pressure
What’s a hurricane?
A violent tropical storm in the Caribbean region
What’s a typhoon?
A violent tropical storm in the Indian and pacific oceans.
What is a tropical storm?
A cyclone, hurricane or typhoon (all the same thing)
Typhoons are usually around Asia e.g. The Philippines
Hurricanes are usually found around America and Mexico
Cyclones are usually found around Northern Australia and East Africa.
What are the conditions necessary for a tropical storm?
Ocean temperatures exceeding 27°C
Water depth of at least 60m
Wind speeds in excess of 74 mph
Low pressure
Fast rotating winds
They occur during the hottest times of the year
What does a tropical storm form?
Warm, moist air rises and condenses into a cloud
More warm, moist air is drawn in
Air rises rapidly in an upward spiral causing high winds
Thick clouds develop which produce heavy rain
Air sinks down the middle of the storm
What features of a tropical storm affect people?
Winds
Storm surges
Heavy rainfall
How do the winds of tropical storms affect people?
Suction can lift roofs and wooden buildings
Destruction caused by flying debris
Trees are uprooted
Power cables are blown down
It can damage trees, crops and flatten forests
Tall buildings collapse - sudden pressure change causes buildings to explode
Wind speeds can average 250 km/h with gusts reaching 360 km/h
How do storm surges from tropical storms affect people?
Combined with high tide, it can increase water levels by over 5m
Results in flooding
Loss of fishing ability
Impacts tourism
Causes issues with sewage
It occurs when the force of the wind piles up water at sea and drives it towards land due to low atmospheric pressure at the centre of the storm.
How does heavy rainfall from tropical storms affect people?
Intense rainfall causes secondary hazards:
- Landslides
- Mass Earth movements / mudslides and mudflows
- Inland flooding by rivers
- The spread of disease due to overflown sewage systems
Heavy rainfall may last several days
How can people and places predict and monitor tropical storms?
Satellites - provide data in the size, intensity and movement of storms
Ships and buoys - provide air and sea surface termperatures, wind speed, wave height, wind direction etc
Aircraft - fly into storms to measure wind speeds, pressure, temperature and humidity
Radiosondes - balloons carrying weather instruments and transmitters are released into storms which also provide data on wind speed, pressure, temp’ and humidity.
Radar - radar images provide information on rainfall
How can people and places protect and prepare themselves for a tropical storm?
Educate people - this prepares people, reducing panic and increasing planning
Plant trees along the coast as a shelter - reduces flooding, holds land together better and acts as wind breaks
Construct levees - prevents storm surges preventing loss of life
Huge tidal gates - prevents flooding from the surges
They can prepare their own survival kits
Buildings can be put on stilts to avoid flood water or roofs can be fixed on more securely
What’s aridity?
Areas where the climate is extremely dry, where precipitation is usually less than potential evapotranspiration
Where do droughts mainly occur?
30° north and 30° south of the equator past the equator but not at a temperate climate yet e.g. North Africa.
However this doesn’t represent all droughts as droughts are defined by individual countries.
What causes a drought?
A prolonged period of insufficient rain which causes crop failures, famines, high food prices and deaths.
What factors affect the severity of the impacts of droughts?
Economics - whether they can afford reservoirs, wells etc. It’s difficult for LEDCs to afford a clean, reliable water supply
LEDCs can’t afford the medicines to treat the increased spread of diseases.
Politics - LEDCs and corrupt governments may result in unequal distribution of water, preventing people from accessing water.
Wars make it harder to get clean water.
Technology - LEDCs struggle to store water/lack of supplies when there is rainfall. Poor technology in LEDCs.
Environment - LEDCs rely on farming so droughts reduce soil fertility and kill crops
Climate - some areas more prone/already arid
Use and users - LEDCs don’t use as much water for leisure so their livelihood and basic needs would immediately be affected.
Social - jobs lost in the primary sector for LEDCs e.g. Fishing, farming.
How can the impacts of a drought be controlled, prevented and limited before the drought?
Create reservoirs to supply water on a needs basis
Construct pipes to bring supplies from non-deficit areas
Pass laws ensuring that all water companies fix leaks immediately
How can the impacts of a drought be controlled, prevented and limited at the time of the drought?
Restrict or prevent car / window cleaning
Encourage showers rather than baths
Use washing/bathing water for plants and gardens
What are the primary hazards of droughts?
Vegetation dies
People and animals die
Soil dries out
Water shortages (which leads to) :
Reduced water supplies for farming
Manufacturing
Industry
Electricity generation
What are the secondary hazards of droughts?
Water tables fall:
- small rivers dry up
- crops fail
- starvation
Land degradation:
- soil erosion
- overgrazing
- deforestation
Wild fires
People and animals starve
Conflicts over water supply
Migration for water supply
Unemployment
Dust storms
What’s desertification?
The degradation of land in arid and semi arid areas resulting primarily from human activities and influenced by climatic variation
It can be due to human mismanagement of fragile environments.
Population increase and poor agricultural practises result in the soul losing it’s protective vegetation cover, leading to soil erosion.
Increased grazing of animals in droughts areas leads to fewer roots to hold soil together.
What are long term and short term responses to drought and which is more sustianable?
L.T. - result in permanent water management measures to secure more water for everyday use e.g. Dams, pipelines and irrigation systems.
S.T. - temporary methods concentrated on reducing water demand and include water rationing, cash and/or food aid.
Short term is LESS sustainable than long term responses and don’t help people to be better prepared meanwhile L.T. methods are expensive and may not improve efficiency.
What are the low tech responses to drought?
Building low walls across fields
Planting trees
Use micro dams
Use stone piles to collect water
Plant drought resistant crops
How does building a low wall across fields respond to the impacts of drought and what are the advantages and disadvantages?
Water is kept on one place and infiltrates and percolates the soil reducing run off.
Adv:
Reduces run off
Saves water
Disadv:
Can obstruct access
