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Extreme Weather
infoWhy this? Tropical storms show how atmospheric processes can produce powerful hazards whose effects depend on both physical exposure and human vulnerability. Studying their formation, impacts, and management helps us understand risk, resilience, and how climate change may alter future hazards.
scheduleWhy now? This unit extends Year 7 knowledge of weather and pressure systems from everyday conditions to extreme events. It also combines the hazard-management framework from tectonics with understanding of coastal and flood risk, creating a strong foundation for the following climate change unit.
neurologyYou need to know
- A tropical storm is a powerful low-pressure weather system that forms over warm tropical oceans and brings strong winds, heavy rain, and thunderstorms.
- Tropical storms usually form between about 5° and 30° north and south of the Equator, where oceans are warm enough and the Coriolis effect can make the storm spin.
- Tropical storms need sea surface temperatures of at least 27°C so that large amounts of warm, moist air can rise from the ocean surface.
- Tropical storms do not usually form directly on the Equator because the Coriolis effect is too weak there to create enough rotation.
- The Coriolis effect is the apparent turning of moving air caused by Earth's rotation, and it helps tropical storms spin.
- Tropical storms are called hurricanes in the Atlantic Ocean and north-east Pacific, typhoons in the north-west Pacific, and cyclones in the Indian Ocean and South Pacific.
- Warm, moist air rises above the ocean, creating an area of low pressure at the surface that draws in more air.
- As rising moist air cools and condenses, it releases latent heat, which gives the storm more energy and helps it grow stronger.
- The eye is the calm centre of a tropical storm, with light winds, little cloud, and sinking air.
- The eyewall is the ring of cloud around the eye, where the strongest winds, heaviest rain, and most intense weather occur.
- Spiral rainbands are curved bands of cloud and thunderstorms that extend out from the centre and bring heavy rain and strong winds across a wide area.
- A more powerful tropical storm usually has a well-organised structure, including a clear eye, a strong eyewall, and tightly curved rainbands.
- Tropical storms often lose strength when they move over land or cooler water because they lose their main source of heat and moisture.
- Primary impacts of tropical storms happen immediately and include deaths, injuries, flooding, storm surge, and damage to buildings, roads, and power supplies.
- Secondary impacts of tropical storms happen later and include homelessness, disease, food shortages, loss of income, and disruption to education and healthcare.
- The impacts of tropical storms vary because places differ in wealth, building quality, emergency planning, healthcare, population density, and exposure to hazards such as storm surges.
- Prediction uses satellites, radar, and computer models to forecast a tropical storm's track, intensity, and likely landfall.
- Planning reduces risk through evacuation plans, emergency services, warning systems, public education, and supplies such as food, water, and medicine.
- Protection reduces damage through storm shelters, sea walls, flood defences, raised buildings, and reinforced building design.
- Climate change can make tropical storms more dangerous because warmer oceans provide more energy, warmer air can hold more moisture, and rising sea levels increase storm surge and coastal flooding risk.
rocket_launchYou must be able to
- Locate the main tropical storm formation zones on a world map, showing that they occur over warm oceans between about 5° and 30° north and south of the Equator.
- Classify tropical storms by regional name, correctly using hurricane, typhoon, or cyclone according to the ocean basin where the storm occurs.
- Sequence the formation of a tropical storm, linking warm ocean water, rising moist air, low pressure, condensation, latent heat, and rotation.
- Annotate a cross-section or satellite image of a tropical storm by labelling the eye, eyewall, and spiral rainbands and describing the weather in each part.
- Explain why tropical storm impacts vary between places, using factors such as wealth, preparedness, building quality, and emergency response.
- Separate the impacts of a tropical storm into primary and secondary impacts, giving accurate examples for each category.
- Evaluate tropical storm management strategies by explaining how prediction, planning, and protection reduce deaths, injuries, and damage.
- Assess why climate change may increase tropical storm risk, linking warmer oceans, heavier rainfall, rising sea levels, and human vulnerability.