Seas defences in Britain and the Netherlands were buffeted by waves over three metres high today, but concerns over flooding receded as it appeared the high tides had peaked.
Surge barriers were closed in both countries, and people were evacuated from their homes as a North Sea storm threatened a deluge in low-lying areas.
But residents were allowed return to their homes in the Norfolk region of Britain as water levels stopped short of historic levels predicted.
While flood warnings remained in place, the UK's Environment Agency (EA) said the main tidal peak in East Anglia, the area most at risk, has now occurred. There were reports of localised flooding, and inland areas affected by different tidal patterns remained at risk.
Prime Minister Gordon Brown chaired an emergency meeting last night and the EA issued eight severe flood warnings as the surge - a combination of gale force winds and a high tide - approached.
The agency had warned of "extreme danger to life and property" in coastal areas of Norfolk and Suffolk and parts of Kent and Essex.
The flood defences of the Dutch coast were put on alert, and the Oosterschelde barrier in the south of the country was closed. The massive storm surge barrier near the Dutch port city of Rotterdam was raised for the first time since its construction in the 1990s.
Shipping to and from Rotterdam is expected to remain suspended until 5pm today.
A Dutch transport ministry spokesman said water levels were expected to reach 2.84 metres above mean sea level. Earlier forecasts had been for more than three metres.