THIS present cold spell in Britain is a mere trifle compared with winters of the past. Forty years ago, the winter was so savage that to everyone it seemed as if a new Ice Age was heading our way.

The coldest winter for more than 200 years began suddenly just before Christmas 1962 with biting winds, followed soon afterwards by blizzards. By early January 1963 much of the country was buried under snow, but South Wales and the West Country caught the worst of it with monstrous snowdrifts up to 6m (20ft) deep.

Villages were cut off for several days and food and medical supplies had to be airlifted in by helicopters. Farmers could not reach livestock and thousands of sheep and cattle perished in the arctic conditions.

The winter was also unusually long. Much of Britain was blanketed in snow continuously from Boxing Day 1962 to early March 1963. As well as that, and in many places across Southern England, the temperature remained stuck below freezing point for the whole of January.

Lakes and rivers froze, and people were ice-skating on the upper reaches of the Thames. Seawater froze along coastlines, harbours were iced over, and ice floes bobbed down the English Channel. Wildlife suffered horribly as animals either froze or starved to death; there were reports of starving foxes battling with badgers over scraps of food.

The winter of 1947 was even more devastating. Britain was suffering greatly after the war and rationing had actually become more severe. Even though the winter was not as cold as 1962-63, the snows were heavier and blocked rail and road transport with drifts more than 4m (13ft) across the country. Coal supplies could not get through to power stations and electricity had to be rationed, while people shivered at home for lack of domestic coal.

Conditions on the Continent were so bad that West Germany was facing starvation and America had to launch the Marshall Plan to save the nation.

Those winters were dreadful, but they were by no means a freak of climate.

Many other winters in the 1940s were cold, as the Germans found to their cost in the invasion of Russia, and the winters of the 1960s and 1970s were also bitter.

It seems that our winter climate swings over decades for reasons not completely understood. However, part of this mystery may lie in a strange flip in the weather systems sitting over the North Atlantic.

Normally, the subtropical Azores area enjoys high pressure and mild weather, while the pressure is low over Iceland, leaving Britain wet and windy.

But the pattern can suddenly and inexplicably somersault, plunging Britain into the cold under a high pressure system, an anticyclone.

Andy Yeatman at the Met Office said: “An anticyclone usually takes a lot of shifting — cold dense air is harder to move than warm wet air. This blocks the cold weather over the UK and can stay for some time.”

This sudden flip in pressure is called the North Atlantic Oscillation. The winters of the 1940s and 1960s were during the negative phase of the oscillation, but since then we have tended to have a much milder run.

Exactly why the North Atlantic behaves like this over decades is a mystery, though.

It has been a long time since anyone has talked seriously about the return of the Ice Age, but if the North Atlantic does another one of its flips we could see the return of Arctic winters to Britain.

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