In the winter of 1953, seawater rose 3 meters above the expected level along the North Sea coast, flooding parts of Britain, the Netherlands and Belgium. A new Cambridge-led study suggests that the places most at risk from such surges can be influenced by climate patterns thousands of kilometers away, across the Atlantic and Arctic.
Storm surges form when strong winds and low air pressure push seawater toward the coast. Tides, waves and the shape of the seabed can make the resulting water levels even higher. The North Sea is especially vulnerable: its narrow shape funnels water toward shore, while its shallow basin can increase the height of a surge. Many people live along its low-lying coasts, where better warnings could help communities prepare.
Led by Lisanne Blok of Cambridge Earth Sciences, the researchers studied 70 years of reconstructed sea-level records from northwestern Europe. They separated the storm-surge part of each record from seasonal changes and other background shifts, then used machine learning to group stretches of coastline where extreme surges tend to happen at the same time. Finally, they compared those regional patterns with broad climate conditions.
The team found that air-pressure differences across the North Atlantic can help point to which U.K. coasts are more likely to face high water. When pressure is low over Iceland compared with the Azores, the jet stream tends to shift north, steering storms over northern parts of the U.K. In that pattern, northern and central coastlines are more likely to experience storm surges. When pressure over Iceland is unusually high, the jet stream can slow and bend south, guiding storms along more southerly paths and raising the risk for southern coasts.
The finding extends what scientists already knew. Large climate patterns help shape storm tracks in northwestern Europe; this study shows they can also help determine where along the coast a surge is most likely to strike. “We can link regional storm surge extremes to very distinct climate patterns,” Blok said, adding that she had not expected such clear links across such large distances.
The stakes are clear from the region’s history. In 1953, a deep low-pressure system moved down the North Sea, pushing water along the east coast. Combined with a high spring tide, it produced levels about 3 meters higher than expected and devastating floods. A 2013 surge brought even higher water levels to Britain’s east coast, but modern flood defenses prevented a disaster on the same scale.
The results do not remove the difficulty of forecasting surges, which depend on winds, pressure and local geography. But identifying climate conditions that favor surges in particular regions could give forecasters more useful clues. If conditions over the Atlantic point toward a greater risk for East Anglia, for example, warnings could focus on the parts of the coast most in need of preparation. The study, published in the Journal of Geophysical Research: Oceans, offers a way to connect distant atmospheric patterns with local flood risk—and potentially give coastal communities more time to get ready.