Special By By Kev Hedges Dec 1, 2010 in Environment Temperatures are set to plunge again overnight tonight after one of the coldest starts to December in more than 20 years has caused chaos throughout the UK. Lakes and small rivers are frozen where normally a gentle stream runs through here. Kev Hedges The Met Office has A back garden in Kilmalcolm, Scotland Published with permission from Andrew Fernie Warnings of avalanches in the Cairngorms have been issued and police have advised people not to travel unless absolutely necessary. The worst-hit areas are Scotland, Yorkshire, Derbyshire and south-east England. In amongst all the disruption however the frost and very low temperatures have produced a white-out spectacle of Christmas card beauty. Water's edge at the breeding lake near Fairlands Valley in Hertfordshire Kev Hedges Temperatures could dip to as low as -27c (-3f) in parts of the Highland region later tonight where drifting snow is some 60cm deep in places, reports The hard frost has created a white-out in the countryside. Here temperatures plunge several degrees lower than in the cities Kev Hedges What has caused the cold snap? An anticyclone (area of high pressure) is sitting to the west of the UK, preventing warm, moist air from the Atlantic reaching the UK, and instead it's drawing in cold air from the Arctic and Scandinavian regions. As this air moves across the North Sea it picks up relatively warm waters, still tempered from the summer and mild autumn and have formed snow showers which have drifted in the biting easterly winds. Rivers in the Fairlands Valley Park are frozen up as temperatures struggle to climb above -3c (27f) Kev Hedges The end of November saw the heaviest falls of snow and some of the coldest temperatures since 1965 in the UK. All trees, shrubs and bushes and every one of their leaves and branches have not escaped a severe frost Kev Hedges More than 4,000 schools are closed, In Scotland, Edinburgh airport is closed and at the other end of the country Gatwick Airport in Surrey is shut until Thursday at least. In the highlands temperatures have plunged to -16c (3f) and tonight it is set to dip even lower.The Met Office has warned strong northeasterly winds and heavy snow showers will lead to further accumulations of 2 to 5 cm, and locally more than 10 cm with some higher parts as much as 20 cm. Drifting of snow is possible, mainly on higher ground.Warnings of avalanches in the Cairngorms have been issued and police have advised people not to travel unless absolutely necessary. The worst-hit areas are Scotland, Yorkshire, Derbyshire and south-east England. In amongst all the disruption however the frost and very low temperatures have produced a white-out spectacle of Christmas card beauty.Temperatures could dip to as low as -27c (-3f) in parts of the Highland region later tonight where drifting snow is some 60cm deep in places, reports BBC An anticyclone (area of high pressure) is sitting to the west of the UK, preventing warm, moist air from the Atlantic reaching the UK, and instead it's drawing in cold air from the Arctic and Scandinavian regions. As this air moves across the North Sea it picks up relatively warm waters, still tempered from the summer and mild autumn and have formed snow showers which have drifted in the biting easterly winds.The end of November saw the heaviest falls of snow and some of the coldest temperatures since 1965 in the UK. More about Winter, Snowfall, Arctic More news from winter snowfall arctic