A storm surge on 5–6 December threatened urban centres and rural communities around the southern North Sea in a similar way to such an event 60 years ago. Causing more than 2,000 deaths, the 1953 flood was western Europe's most devastating in 100 years in terms of loss of life. Last month, however, a disaster was averted by advances in storm-surge forecasting, improved defences, early-warning systems and integrated crisis management.

Immediately after the surge, we made high-resolution measurements of maximum water levels, focusing on obvious debris lines, erosion points on earthen bank defences and water marks on buildings along the 45-kilometre-long northern coastline of Norfolk in the United Kingdom. These confirm that flood levels were similar to, and in places exceeded, those in the 1953 disaster.

There was considerable variation in the mean height of peak water levels along the shore (the maximum difference between measurement stations was more than 1.2 metres). This reflects the combined effects of tide, surge and wave run-up, which has a strong local component. For this coastline of barrier islands, spits and tidal embayments, these observations indicate that the coastal setting and extent of coastal ecosystems (such as mudflats and salt marshes) are critical in determining the pattern of storm-surge impacts.

Such differences become crucial when properties, infrastructure and lives are threatened by sea flooding (see also J. D. Woodruff et al. Nature 504, 44–52; 2013). These factors should be incorporated into hydrodynamic modelling and forecasting efforts, to help fine-tune early-warning systems and evacuation planning.