A rare combination of high tides and storm-force winds from the north and north-west are the nightmare scenario that creates flooding on the Norfolk and Suffolk coast.

Norwich-based Weatherquest forecaster Jim Bacon explained that the two elements last combined to great effect on November 9 2007, when Great Yarmouth was hit particularly hard by surging water.

He said: 'The first factor is the high tides that are caused by the gravitational pull of the moon. When the moon is aligned with the sun, you get unusually high tides that are called spring tides.

'Usually they happen a day or two after the new moon or the full moon.'

Mr Bacon added: 'The other factor, which cannot be predicted far in advance, is the weather. If you get a strong onshore wind - blowing from the sea towards the land - it makes the tide higher by pushing the water towards the land.

'The big storm system that is over Scotland and building over Scandinavia has the effect of pushing the water down the North Sea, which narrows as it goes south. There is only one way the water can go. A mass of water comes southwards.

'When these two combine, the difference in the tides can be significant.'

Mr Bacon said low air pressure also played a part, as it did not push down on the surface of the sea, allowing it to rise.

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