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Storm surge & coastal flooding
Low-pressure storms + spring tides + onshore wind. The 1953 east-coast vector.
Context
Storm surge is the combination of low atmospheric pressure raising sea level (~1 cm per 1 hPa drop) and onshore wind piling water against the coast. Combined with a high spring tide, surges can overtop sea defences. The 1953 North Sea flood killed 307 in the UK and 1,800 in the Netherlands. The Thames Barrier exists because of that event.
When this matters
Met Office wind warning *and* a spring tide *and* onshore wind for your coastline. EA / SEPA / NRW issues a coastal flood warning.
Before
- Check tide times for the storm window — the surge effect compounds with high tide.
- East coast England: pay special attention to North Sea surges in winter with N or NE wind.
- South coast / Severn Estuary / Bristol Channel: bore-tide effects amplify surge.
- Move vehicles uphill well before the predicted high water.
- Sandbags or property barriers if you're in a known surge zone.
During
- Don't go to the seafront to watch. Seawall overtopping has killed tourists in every recent UK surge event.
- Don't drive coast roads during surge windows — they flood without warning.
- Stay above the projected high water in your property if surge is imminent.
After
- Salt water damage is worse than fresh — corrosion of utilities and structural metalwork can take weeks to manifest.
- Sand and debris in drains will need clearing before the next high water.
- Coastal beach changes can be substantial after a surge — check before swimming for at least a week.
UK specifics — numbers, sources
- Storm Tide Forecasting Service (Met Office + NOC) issues UK coastal flood warnings.
- EA Coastal Flooding alerts: gov.uk/check-flood-risk (covers coastal in England).
- HM Coastguard: 999 → Coastguard for any maritime / cliff / beach emergency.
- Surge of >1 m is significant; >2 m is a major event with overtopping likely.
General guidance. Your specific circumstances may vary — follow the Met Office, Environment Agency / SEPA / NRW, your local council, and emergency services for situation-specific direction. See the code of conduct for chasers in the field.