Weather Hazards

GeographyAQAGCSEUnit: The Challenge of Natural Hazards
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The basics

The Storm That Rewrote the Record Books

🌀 The Storm That Rewrote the Record Books

At 4:40am on 8 November 2013, Typhoon Haiyan made landfall near Guiuan on the island of Samar, Philippines. The sustained wind speed was 195 mph (315 km/h) — the highest ever recorded for a landfalling tropical storm in human history. The storm did not just blow things down. It pushed the sea.

A wall of water 7.5 metres high — taller than a double-decker bus standing on top of another — rolled inland across the city of Tacloban. People had been warned about the wind. Almost nobody had told them what a storm surge would look like. Families climbed into their attics to escape flooding. The surge followed them there. The wind did not kill most of Typhoon Haiyan's 6,300 victims. The sea did.

Within 24 hours, 80% of Tacloban had been destroyed. Over four million people were displaced across the Visayas islands. Economic damage reached $12 billion. Haiyan was not just a meteorological event — it was the product of warm tropical oceans, a vulnerable coastline, poverty-built housing, and a population that had never been told that the sea, not the sky, was the most dangerous part of the storm.

Understanding weather hazards means understanding not just how storms form, but why some storms become catastrophes and others do not. The physics of the atmosphere is only half the story.

What is a storm surge?: A rise in sea level caused by low pressure and strong winds pushing water toward the coast.
Key terms

Geography glossary

What is a storm surge?
A rise in sea level caused by low pressure and strong winds pushing water toward the coast.
What is a tropical storm?
An intense rotating storm that forms over warm tropical oceans.
Spotlight
What Are Weather Hazards?

A weather hazard is any atmospheric event that poses a serious risk to people, property, or the environment. Unlike tectonic hazards — which are driven by forces deep inside the Earth — weather hazards are driven by energy in the atmosphere, primarily the uneven heating of the Earth's surface by the Sun.

Exam tip

Earn the mark scheme marks

🧠 STORM — The Formation Mnemonic

Remember the key features of tropical storms with STORM:

S — Surge kills most people, not the wind. In Typhoon Haiyan (2013), the 7.5 m storm surge was the primary killer — not the 195 mph winds. Always lead with surge when explaining tropical storm deaths in exam answers.
T — Track away from tropics over warm water, weakening over cold water or land. Storms track initially westward (steered by trade winds), then recurve poleward. They weaken when they lose their warm ocean fuel.
O — Ocean temperature ≥26°C required for formation and maintenance. This is the storm's fuel. No warm water = no storm forms. Ocean cooling = storm weakens. Climate change is expanding the area of ocean above 26°C.
R — Rotation caused by the Coriolis effect. Anticlockwise in Northern Hemisphere; clockwise in Southern. Zero rotation at the equator — that's why storms cannot form there (the Coriolis effect is zero at 0° latitude).
M — Monitoring reduces death toll in HICs by providing 5–7 days' track warning. The gap between warning and survival is bridged by preparedness: evacuation capacity, building quality, surge awareness. Monitoring is most effective when combined with planning and protection.

Somerset Levels Cause Mnemonic: DRIPS

  • D — Dredging not done since early 1990s — river capacity reduced by 20+ years of sediment accumulation
  • R — Record rainfall — 200% of average in January 2014; wettest winter in 250 years
  • I — Inundation of 17,000 acres; 600+ homes; villages isolated for weeks by road
  • P — Policy debate — managed retreat (Environment Agency) vs active dredging (local communities); Somerset Flood Action Plan (£100m) introduced as resolution
  • S — Saturated ground from autumn 2013 storms — no infiltration capacity left when winter rains arrived

Primary vs Secondary Effects: Punch vs Slow Burn

  • Primary = P for Punch — the storm's direct physical punch: wind damage, surge flooding, rainfall flooding. Happens during the event. Affects everyone equally regardless of wealth.
  • Secondary = S for Slow Burn — consequences that develop slowly after the storm passes: disease, displacement, economic disruption, psychological trauma. Shaped heavily by vulnerability — how quickly society can restore water, provide shelter, fund reconstruction.

Now try it yourself

Quiz · Question 1 of 16

What is the minimum ocean surface temperature required for a tropical storm to form?

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