North Sea Surges

The Major Flood Risk to East Anglia

When a number of natural factors coincide, a grave risk of sea rise and consequent flooding results for the low laying East Anglian coastline and inland areas. The combination of factors produce what is known as a ‘North Sea Surge’. Here are those factors…

1) High Northerly Lunar Declination

Contrary to common belief, the moon does not orbit earth, but orbits the sun with earth, producing an eccentric orbit not calculable by the normal Keplerian data. At times one will see the moon rise in the south east, elevate up to perhaps only10 degrees above horizon in the south, to set in the south west. At other times our only natural satellite will rise in the north east, ascend to up to 60 degrees of elevation above the horizon at the most southerly point, to sink in the north west. This latter condition is known as a ‘high northerly lunar declination’. The gravitational pull of the moon is far higher at such times, so reducing earth’s compaction pull, so producing higher tide levels.

2) Lunar Perigee

Our moon does not perform a uniform circular path orbit in its 28-day period around earth either. At apogee, the highest point, it is 406,697 kilometres (252,710 miles) from earth, whilst at perigee it reduces to only at 356,410 km (221,463 miles). When perigee occurs, the lunar gravitational field pull is increased, so reducing earth’s pull, so producing far higher sea levels. These are particularly noted in the equinoxes, and are known as ‘Spring Tides’.

3) Full and New Moons

When the Sun and the moon are at opposite ends of the earth the moon is fully illuminated, and we see a ‘full moon’. At this time the fluid tides form an ellipse around earth, with water movement to both the sun and the moon. Further, when the sun and moon are on the same side of earth and we see a ‘new moon’ the sun and moons gravitational pulls combine, pulling the water toward them, this also giving higher tides. The tidal height is not maximised at full moon or new moon, but due to flow delay, occurs some two days after the new and full moon. The moon over the equator produces even higher ‘proxigean’ tides because the volume of water effected is far greater there. If all the above factors occur simultaneously, then we experience very high tides indeed. Man does not have the technology to do anything whatsoever about this condition.

4) Weather Factors – Deep Barometric Lows

Barometric pressure exerts a powerful influence on tide levels. Whilst the high-pressure systems that normally come about in the summer months reduce sea levels an increase of tidal peak height is produced with a fall in barometric pressure. Each millibar drop will produce a rise of 1 centimetre in sea level. When deep lows appear over the southern North Sea (as is now happening far more frequently and to a greater degree as Global Warming continues to escalate) we experience far greater sea rises.

5) High Inland Rainfall

High levels of rainfall can come about from the weather fronts circulating round a deep depression. Over the course of two to three days these will add to river levels and flows, which will restrict sea escape to estuaries such as Breydon Water. River outflow will be limited by high sea levels; with the result that severe flooding can come about even in low laying riverside villages and towns.

6) High and sustained northerly wind Factors

The deep barometric lows as already referred to above are accompanied by isobars around them. The greater the compaction of the isobar lines the greater is the wind velocity. Whilst barometric highs show circularly rotating winds, low-pressure systems demonstrate anti-clockwise circular rotation. When a deep and sustained low comes over the British Isles from the west to over the North Sea, strong winds come from down the north, pushing the sea down to the constricted and shallow English Channel as depicted by Fig.2. The water cannot escape, and mounds. Each successive high tide is added to by the next, so the sea level rises all along the eastern seaboard. If the low is closely followed by a high-pressure system to the west, then the anti-clockwise winds rotating around the low are reinforced by the circularly rotating winds around the high to the west, further compacting the isobars and producing even stronger wind velocities and sea levels. A Beaufort Force 9 north-westerly, north-north-westerly or a northerly can raise East Anglian marine tide levels more than 2 metres above the normally predicted high. Furthermore, the high wave heights produced on facing coastlines (the eroding power of a wave is proportional to the square of the crest height) can scour the beaches of sand and shingle to undermine and damage sea defences, even overtop them. With Global Warming, such winds are becoming stronger, more frequent, and last for longer.

East Anglian Sinking

One further factor comes into the equation. Tectonic plate shift impaction between the North American Plate and the Eurasian Plate is gently reducing, causing Scotland to slowly rise from the sea. The tip effect produced is causing East Anglia and eastern Kent to sink. This was thought to be at a rate of some 3mm per year in the past, but thankfully now considered reduced to some 1.5mm per annum. Although the rate is small, it dictates a considerable inland movement of the sea in flat low laying areas.


Summarizing, critical danger conditions are brought about by a combination of the above six factors, not necessarily all of them. (The disastrous North Sea surge of 1953 that drowned over 300 people did not come on the highest tide). Should the conditions ever all appear together, a calamity will result, with sea levels over 2 metres higher than those experienced in 1953. Although the statistical chances of this coming about are probably less then one in a thousand, it will happen one day. It is not IF it will happen, but WHEN. It may occur this February, or the next, or the next, and hopefully not for fifty more years. But what is for sure, the impact of increasing ‘greenhouse’ emissions, of continuing offshore aggregate dredging and the lack of national government capital provision for adequate coastal protection are increasing that chance year by year. The ingredients are:-

  1. The moon high in the northern hemisphere sky (high northerly lunar declination)
  2. The moon at or close to perigee, e.g. closest to earth.
  3. Two days following a new or a full moon.
  4. A deep low-pressure system over the North Sea, particularly with a following high.
  5. High level sustained inland rainfall plus ca, 2 – 3 days.
  6. A severe and sustained NNW wind, +/- 30 degrees.


storm track from the Environment Agency for 1953 flood

This storm track from the Environment Agency shows how the deep low came across the Atlantic then down the North Sea to give the sea rise and sustained strong gale that brought about the 1953 flood disaster. It was not on the highest tide.

map showing areas at risk

The areas in blue show the flooding that can occur in north and east Norfolk in a surge like that of 1953.


The Environment Agency map

The Environment Agency map shows the height over and above that predicted that arose in the 1953 floods. The next could be as much as 2.5 metres above this.


webcam image

North Sea Surge captured by the BBC webcam at 9.25 am 20th March ’07, showing the huge waves and offshore sea mound seen by the pier at Cromer Beach

Pat Gowen, 16th October 2001

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