The Challenge of Natural HazardsTopic Summary
Topic Summary: Weather Hazards
Part of Weather Hazards — GCSE Geography
This topic summary covers Topic Summary: Weather Hazards within Weather Hazards for GCSE Geography. Revise Weather Hazards in The Challenge of Natural Hazards for GCSE Geography with 15 exam-style questions and 24 flashcards. This topic shows up very often in GCSE exams, so students should be able to explain it clearly, not just recognise the term. It is section 14 of 14 in this topic. Use this topic summary to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 14 of 14
Practice
15 questions
Recall
24 flashcards
Topic Summary: Weather Hazards
Key Terms
- Tropical storm: Intense rotating low-pressure system over warm tropical ocean (≥26°C); called hurricane (Atlantic), typhoon (Pacific), or cyclone (Indian Ocean)
- Storm surge: Dome of ocean water pushed onshore; typically the deadliest component of a tropical storm
- Coriolis effect: Earth's rotation deflects moving air — right in NH (anticlockwise storms), left in SH (clockwise storms); zero at equator
- Eye: Calm, cloudless centre with lowest pressure; 20–65 km diameter; sinking air suppresses clouds
- Eyewall: Ring of most intense winds and rainfall surrounding the eye
- Latent heat: Energy released when water vapour condenses — the positive feedback that drives storm intensification
- Managed retreat: Allowing rivers to flood naturally; reduces maintenance cost but conflicts with farming and habitation
- Rhynes: Drainage channels on the Somerset Levels; when blocked by sediment, flood risk increases
Key Dates and Statistics
- 8 November 2013: Typhoon Haiyan landfall, Philippines
- 195 mph (315 km/h): Haiyan wind speed — strongest landfalling storm ever recorded
- 7.5 m: Storm surge height in Tacloban — primary cause of deaths
- 6,300+: Deaths from Haiyan; 4.1 million displaced
- $12 billion: Economic damage from Haiyan
- 26°C: Minimum ocean surface temperature for tropical storm formation
- 5°–20°: Latitude band where tropical storms form
- Winter 2013–14: Wettest winter in England and Wales for 250 years
- 17,000 acres: Flooded on Somerset Levels; 600+ homes
- 200%: Of average rainfall received in Somerset, January 2014
- £100 million: Somerset Flood Action Plan cost
Key Places
- Philippines: Western Pacific typhoon belt; among world's most typhoon-prone nations
- Tacloban, Leyte: City destroyed by Haiyan surge; 80% of structures damaged or destroyed
- Somerset Levels, SW England: Flooded winter 2013–14; drainage managed since medieval times
- Rivers Tone and Parrett: Main drainage rivers of Somerset Levels; un-dredged 1990s–2014
- Muchelney and Thorney: Villages isolated for weeks during Somerset flooding
- Western Pacific Ocean: World's most active tropical storm basin
Must-Know Facts
- Tropical storms CANNOT form at the equator — Coriolis effect = 0 there
- Storm surge kills more people than wind — always specify this in answers
- NH storms rotate anticlockwise; SH storms clockwise (Coriolis deflects right in NH, left in SH)
- Storms form over warm water (≥26°C); weaken over land or cool water
- Three risk-reduction approaches: monitoring/prediction, planning, protection
- LICs have higher death tolls due to structural vulnerability: housing, evacuation, awareness, wealth
- Somerset: record rainfall + saturated ground + un-dredged rivers + low-lying topography = severe flooding
- Post-Haiyan: Philippines now separates surge warnings from wind warnings — direct lesson from 2013
- Mangroves can reduce surge wave energy by 50–70% — natural coastal protection
- Climate change → warmer oceans → more intense storms; rapid intensification becoming more common