Storm Hazards Flashcards
What are tropical storms?
1) Tropical storms are huge spinning storms with strong winds and torrential rain.
2) They develop over warm water, As warm, moist air rises and condenses, it releases energy that increases wind speed.
3) Scientists don’t know exactly how they’re formed but they do know the conditions needed. These include:
>A disturbance near the sea surface that triggers the storm.
>sea water that’s warm, so lots of water will evaporate.
>Convergence of air in the lower atmosphere- either within the ITCZ or along the boundary between cold and warm air masses.
4) Tropical storms form in the tropics because the water there is warm enough.
5) Tropical storms lose strength when they move over land because their supply of warm, moist air is cut off.
6) They initially move westwards due to the easterly winds in the tropics e.g. trade winds move cyclones west across the Atlantic Oceans.
7) They move away from the Equator because of the Coriolis effect.
Tropical storms are circular
1) Tropical storms are circular in shape, hundreds of kilometers wide, and usually last 7-14 days. They spin anti-clockwise in the northern hemisphere and clockwise in the southern hemisphere.
2) At the center of the storm is an area of very low pressure called the eye.
3) Rising air spirals around the eye in the eyewall, causing strong winds.
4) Near the top of the storm, there is an outflow of moisture-laden air, so cloud cover extends for a long distance on either side of the eye.
What’s the Saffir-Simpson Scale?
1) Storms are classified using the Saffir-Simpson Scale, which is based on wind speed. Category 5 is the strongest and 1 is the weakest.
2) The Saffir-Simpson Scale also estimates how much damage a storm of a given magnitude will do, from limited damage at category 1 and catastrophic damage at category 5.
Storm hazards can take a number of forms:
High winds- wind speeds on the ground can reach up to 300km/h. Wind can destroy buildings, uproot trees and carry debris long distances before crashing into other objects.
Storm surges- a storm surge is a large rise in sea level caused by high winds pushing water toward the coast, and by the low pressure of the storm.
Heavy rain- as warm, moist air rises it cools and condenses, causing torrential rain.
Flooding- heavy downpours can cause river discharge to increase suddenly, causing rivers to overtop their banks and flood the surrounding area. Heavy rain and storm surges can also cause flooding in coastal areas.
Landslides- water infiltrates soil and rock, making it less stable and increasing the risks of landslides.
How do storm hazards have impacts socially, economically, environmentally, and politically?
Social:
>People may drown, or be injured or killed by debris that’s blown around or carried in floodwater.
>Houses are destroyed so people are left homeless.
>Electricity cables are damaged and supplies are cut off.
> Flooding causes sewage overflows, contaminating water.
> The lack of water can cause diseases.
> Damage to agricultural land can cause food shortages.
Economic:
> Buildings and infrastructure cost a huge amount to rebuild.
> Businesses are damaged or destroyed, so they cant trade.
> Agricultural land is damaged, affecting commercial farming.
Environment:
> Beaches are eroded and coastal habitats are damaged.
> Environments are polluted e.g. by salt water, oil, and chemicals spilled from damaged factories.
> Landslides can block watercourses, so they change course.
Political:
> People may blame the authorities for shortages of food, water, and energy, leading to conflict and political unrest.
> Expensive repairs to buildings, infrastructure, etc. limit the amount of money that can be spent on development.
What are the responses aimed to reduce the impacts of storm hazards?
Prevention:
> Storms cannot be prevented, but they can be studied to help scientists understand which areas are most likely to be affected.
Preparedness:
> Emergency services can train and prepare for disasters, and governments can plan evacuation routes to get people away from storms quickly and educate people about how to prepare for a storm.
Adaption:
> Buildings can be designed to withstand tropical storms e.g. by using concrete or by fixing roofs securely so they’re not blown off. Buildings can also be built on stilts so they’re safe from floodwater. Flood defenses can be built along rivers and coasts.
