storm hazards

what is a tropical storm

a low pressure, spinning storm with high winds and torrential rain

what are the conditions needed for a tropical storm to develop

• ocean temperatures must be around 26-27*C

• must be in an area of unstable air pressure (usually when areas of high pressure and low pressure meet)

• must be at least 5* latitude from the equator for the Coriolis effect to create rotation

• a trigger must be present, such as a pre-existing thunderstorm, and spot of very high sea surface temperature or an area of low pressure

describe the formation of tropical storms

1. the heat from the ocean causes rapid evaporation of water, creating warm moist air. This air rises, creating an area of low pressure at the surface.

2. as the air rises, it cools and condenses into clouds. This releases latent heat, which fuels further uplift and makes the system more powerful.

3. More air is drawn into the low-pressure centre. Due to the Coriolis effect, the air starts to spiral, creating a rotating system.

4. the storm organises into:
   - eye (calm, sinking air, very low pressure)
   - eyewall (strongest winds and heaviest rain)
   - spiral rain bands

5. continuous supply of heat and moisture causes stronger winds and lower pressure

when might tropical storms weaken

• move over land (cut off from warm water)

• move over cooler water

• encounter strong wind shear

what happens when the tropical storm reaches a coast

• the low pressure and high winds will cause a large amount if sea water to be taken into the system

• the sea water is then releases as a high wave called a storm surge

how are tropical storms measured

on the Saffir- Simpson Scale (a scale of 1-5), based on wind speed.

when do tropical storms form in the Northern Hemisphere vs the Southern Hemisphere

Northern Hemisphere- June to November

Southern Hemisphere- November- April

do the majority of tropical storms develop into strong storms and reach land

no

how is climate change changing the frequency and strength of tropical storms

tropical storms that are higher magnitude and reaching land are thought to be increasing in frequency

discuss the regularity of tropical storms

they are irregular because although they occur in the same areas, their path does not follow a set route- the route is dependent on the storm and the climatic conditions

discuss the predictability of tropical storms

• they form away from land, meaning satellite tracking of cloud formations and movement can be tracked and the general route can be predicted.

• the closer the hurricane gets, the easier it is to predict

• storm surges can also be predicted based on the intensity of the storm

• from past storms and climatic trends, the probability of a storm hitting an area can also be predicted.

give some hazards caused by tropical storms

• high winds- over 300km/h and therefore very strong. Hurricane winds are strong enough to blow a house down, and also blow heavy debris at high speeds

• flooding- coastal/river flooding from storm surges and heavy rain. River flooding also sends more floodwater to other places, which can cause areas outside of the tropical storm’s path to flood also.

• landslides- due to soil becoming heavy when wet with high levels of rain

• storm surges- large rise in sea levels caused by low pressure and high winds, pushing water towards the coast.

give some primary effects from storms

• beaches eroded

• coastal habitats such as coral reefs destroyed

• businesses destroyed

• agricultural land damaged

• drowning

• debris carried by high winds can injure or kill

• government buildings destroyed

give some secondary effects of storm hazards

• river flooding/ salt water contamination

• animals displaced from flooding

• rebuilding and insurance payout

• sources of income lost

• homelessness

• polluted water supplies spread disease

• food shortages from damaged land

• issues paying back international aid

• pressure for government to do more about global warming

what are the 4 categories of response and risk management to storm hazards

prevention, preparedness, mitigation, adaptation

discuss how storm hazards can be prevented

• they cannot be avoided

• however, strategies to mitigate climate change could prevent higher category storms

discuss how you could prepare for storm hazards

• awareness through education of what to do during a tropical storm

• evacuation plans and training

• satellite image tracking to manage the areas that are at risk

• storm warning systems and television broadcasts tracking the storm

discuss how storm hazards can be mitigated

• search and rescue, immediate emergency aid, evacuations

• strengthening the home through door barricades, roof strengthening etc.

• clearing loose debris before the storms

discuss how people can adapt to storm hazards

• move away from the area at risk

• design buildings to withstand high winds and flood damage

• flood defences such as houses on stilts, coastal walls, river levees etc.