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Spec mapping (AQA 7037): Paper 1 (Physical), §3.1.5 Hazards — storm hazards: detailed case studies of tropical-storm events at contrasting locations and scales, demonstrating their causes, impacts (primary/secondary; social, economic, environmental) and the short- and long-term human responses. This lesson applies the storm physics of the previous lesson to four contrasting events — Typhoon Haiyan 2013, Hurricane Katrina 2005, Cyclone Nargis 2008 and Hurricane Maria 2017 — chosen to vary physical intensity, coastal vulnerability and development/governance context so that the risk equation can be tested. It links to §3.2 (coastal population/urban vulnerability) and to the management lesson. Assessment objectives: AO1 (the events and their hazards), AO2 (applying storm and vulnerability theory to each located case) and AO3 (comparing and evaluating intensity, surge, casualty and economic data across development contexts).
The organising question is the same one that runs through the tectonic case studies: why do storms of comparable physical magnitude produce such different impacts? These four cases are a deliberate natural experiment. Nargis (Category 4) killed ~138,000 while Haiyan (the more intense Category 5) killed ~6,300 — the weaker storm being ~22 times deadlier — which, as with Haiti and Chile, can only be explained by the Vulnerability and Capacity terms, not the Hazard term. Maria, meanwhile, demonstrates a high-income territory's catastrophic, drawn-out failure of governance and infrastructure, and Katrina exposes deep social vulnerability within the world's richest country. Holding Risk = (Hazard × Vulnerability)/Capacity in view, the task is to use precise located figures to show which term dominated in each case — and the technique, as always, is to deploy data in service of an argument rather than reciting it.
These four cases also span the full development spectrum in an instructive way. Two struck lower-income or politically-marginalised settings (Nargis in junta-ruled Myanmar; Maria in a fiscally-broken US territory), one a lower-middle-income but highly storm-exposed state (Haiyan in the Philippines), and one the wealthiest country on Earth (Katrina in the USA). The fact that the highest death toll occurred not in the poorest by GDP but in the one with the most catastrophic governance (Myanmar), and that thousands died in the wealthiest country (the USA, across Katrina and Maria), is exactly what makes the set so powerful for dismantling a crude "development determines impact" thesis. The lesson the cases teach together is that how a society is governed, and how equitably its capacity is distributed, can matter as much as its aggregate wealth.
It helps to distinguish, from the outset, the kinds of vulnerability that recur across these cases, because a strong answer names them precisely. Physical (or locational) vulnerability is about where people are — on a flat delta, behind a levee below sea level, on a low-lying coast — and is largely a matter of geomorphology and exposure. Social vulnerability is about who people are — the poor, the elderly, the disabled, the carless, ethnic minorities and the chronically ill are systematically less able to prepare, evacuate, survive and recover. Economic vulnerability concerns the resources a household or society can fall back on. And institutional or governance capacity concerns whether the state can forecast, warn, evacuate, rescue, restore infrastructure and rebuild — and whether it chooses to do so equitably. Across the four cases, physical vulnerability is starkest in the Irrawaddy and Mississippi deltas, social vulnerability is the heart of the Katrina and Maria stories, and governance failure is most extreme in Nargis — but in every case it is the interaction of these with the physical storm that determines the outcome.
| Category | Details |
|---|---|
| Deaths | ~6,300 confirmed; ~1,000+ missing |
| Displaced | ~4.1 million |
| Storm surge | Up to ~5–7 m in Tacloban — the primary killer; the funnel of Leyte Gulf amplified it |
| Infrastructure | ~1.1 million homes damaged or destroyed; ~33 million coconut palms flattened (crippling the copra industry); Tacloban airport wrecked |
| Economic | ~US$12.9 billion in damage |
| Livelihoods | Fishing fleets destroyed; farmland salinised by surge |
Haiyan's deaths were overwhelmingly caused by storm surge, not wind — and crucially by a failure of risk communication. Warnings were issued and evacuations were ordered, but many residents did not understand the unfamiliar term "storm surge" and expected a wind event, so they sheltered in coastal buildings that the ~5–7 m wall of water then destroyed; some designated evacuation centres were themselves inundated. This is a profound lesson for the Capacity term: a warning only saves lives if it is understood and acted upon, so effective early warning is a communication problem as much as a forecasting one.
It is worth dwelling on why the surge was so deadly at Tacloban specifically, because it shows physical and social vulnerability compounding. Tacloban sits at the head of Leyte Gulf, a funnel-shaped embayment that concentrated and amplified the surge exactly as the storm-dynamics lesson predicts; the city is low-lying and densely settled, with extensive informal coastal housing of light materials offering no protection; and the population had no living memory of a surge of this scale, so even those who heard the warning underestimated it. The Philippines, despite its high baseline exposure, was a lower-middle-income country with limited resources to harden coastlines or build robust shelters — economic vulnerability constraining Capacity. The disaster also overwhelmed local response capacity entirely: Tacloban's own officials, police and hospitals were themselves victims, so the immediate response had to come from outside, and the airport's destruction slowed the arrival of aid in the critical first days.
The international response was large (over US$1.2 billion in aid; the US carrier USS George Washington and the UK's HMS Illustrious deployed), and the long-term "build back better" programme introduced tougher building standards, "no-build zones" along the most exposed coast, mangrove replanting to buffer future surges, and disaster-risk reduction in the school curriculum — a constructive example of converting a catastrophe into improved resilience. Critically, the surge-communication failure prompted a change in warning language, with agencies now issuing explicit, height-specified surge warnings and using more vivid, locally-meaningful terms — a direct, learned improvement in the Capacity term that has plausibly saved lives in subsequent typhoons.
| Category | Details |
|---|---|
| Deaths | Officially 64 initially, but a Harvard/George Washington University study estimated ~2,975–4,600 excess deaths over the following months |
| Power | The entire island lost electricity; some areas had no power for ~11 months — the longest blackout in US history |
| Infrastructure | Water, communications, roads and hospitals crippled; medical care collapsed for the chronically ill |
| Economic | ~US$90 billion in damage |
| Demographic | Tens of thousands emigrated to the US mainland, accelerating depopulation |
Maria is the essential case for showing that "high income" does not equal "low vulnerability," and that the aftermath can kill far more than the storm. The direct storm deaths were modest, but the collapse and non-restoration of critical infrastructure — above all the electricity grid, on which water pumping, sewage treatment, hospitals, dialysis machines, ventilators and the refrigeration of insulin and other medicines all depend — caused thousands of excess deaths over the following months, overwhelmingly among the elderly and chronically ill who could not access the power-dependent care they relied on. This is a critically important and modern insight: in a developed, infrastructure-dependent society, the loss of the systems that sustain daily life can be deadlier than the storm's direct violence, and the death toll accumulates slowly, long after the cameras have left.
The gulf between the initial official toll (64) and the later scholarly estimate (~2,975–4,600 excess deaths) became a political scandal and a textbook example of how death tolls are contested and often undercounted, especially when deaths are indirect — a person who dies weeks later because their dialysis clinic has no power is a storm victim, but is easily omitted from the official count. The episode is therefore also a lesson in the politics of disaster data. The slow and widely-criticised federal response to a territory — whose ~3.4 million residents are US citizens but have no vote in Congress and no voting representation — raised pointed questions about political marginalisation and equity within a wealthy state, a direct parallel to Katrina's exposure of who is, and is not, prioritised. Pre-existing economic vulnerability mattered too: Puerto Rico was already in a severe debt crisis with a chronically under-invested, ageing grid, so the storm struck a system with no resilience and the resources to rebuild it were contested. Maria demonstrates that Capacity is not simply a function of national wealth but of the condition and resilience of infrastructure, the equity of attention a place receives, and the political will and resources to restore essential services quickly. The longer-term consequences compounded the tragedy: the prolonged blackout and economic damage drove tens of thousands of (especially younger, working-age) residents to emigrate to the US mainland, accelerating Puerto Rico's pre-existing depopulation and ageing and weakening the very tax base and workforce needed to fund recovery — a self-reinforcing downward spiral that the Park model captures as a failure to return to the pre-disaster level of activity. Maria thus illustrates how, in a fragile economy, a single storm can trigger long-run demographic and economic decline far out of proportion to its physical footprint.
| Category | Details |
|---|---|
| Deaths | ~1,836 |
| Displaced | Over 1 million; ~400,000 from New Orleans |
| Flooding | Levee failures — an engineering failure, not just the storm — flooded ~80% of New Orleans, up to ~6 m deep |
| Economic | ~US$125–161 billion — among the costliest US disasters |
| Social | Impacts fell disproportionately on low-income, African-American communities (the Lower Ninth Ward); the elderly and disabled were most at risk |
Katrina is the defining case of social vulnerability and infrastructure failure within a rich country. The flooding of New Orleans was caused not simply by the surge but by the failure of the federal levee system — a foreseeable engineering shortcoming, since the levees had been built to a standard known to be inadequate for a major hurricane — so the disaster was in large part human-made. The geography compounded it: much of New Orleans lies below sea level in a bowl between the Mississippi and Lake Pontchartrain, so once the levees were breached the water had nowhere to drain and ~80% of the city flooded to depths of up to ~6 m, trapping those who had not left.
The social dimension is what makes Katrina a set-text in hazard geography. The mandatory evacuation order came late and, fatally, no public transport was provided for the ~100,000 residents who had no car — overwhelmingly the poor, the elderly, the disabled and the predominantly African-American community of districts like the Lower Ninth Ward — so the capacity to evacuate was unequally distributed along lines of race, income and mobility. Those who could not leave sheltered in the Superdome and Convention Center in conditions that became notorious, and FEMA's slow, disorganised response (its director resigned) showed that institutional capacity can fail even when national wealth is enormous. The episode gave rise to widespread discussion of "environmental racism" — the idea that the burden of environmental hazards falls disproportionately on marginalised communities — and to a re-examination of how the world's richest country could fail so visibly. Recovery, too, was inequitable: the levee system was rebuilt as a US$14.5 billion upgraded defence, but New Orleans's population recovered to only ~80% of its pre-storm level, and the poorest, lowest-lying neighbourhoods never fully returned, with some effectively depopulated. Katrina is the proof that vulnerability is socially differentiated — who suffers depends on race, income, age and mobility — and that wealth at the national scale does not guarantee protection at the household scale, a distinction central to the whole topic.
| Category | Details |
|---|---|
| Deaths | ~138,000 (≈84,500 confirmed; ≈53,800 missing) — the deadliest cyclone in the Indian Ocean basin |
| Displaced | ~2.4 million |
| Storm surge | ~5 m, penetrating up to ~40 km inland across the flat delta |
| Infrastructure | 700,000+ homes destroyed; ~75% of health facilities damaged; rice paddies salinised |
| Economic | ~US$10 billion (~60% of GDP) |
| Food security | The delta is Myanmar's "rice bowl"; ~65% of paddy flooded with saltwater, threatening famine |
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