The predicted blanket of snow is expected to bring Britain's transport network to its knees this weekend.
Up to 12in (30cm) of snow is expected to fall on higher ground over the course of the next 24 hours, and most of the UK is likely to see a covering of between five and 10cm of snow.
In addition, weather experts' predictions that it would be bitterly cold in England have proved to be correct, as temperatures are unlikely to rise above zero.
The Highways Agency has issued an amber alert to drivers, and motorists are advised to take extra care and check weather forecasts before they travel.
South east Wales and the south west of England are expected to see the worst of the weather conditions.
Met Office warning
Blizzards and winds of at least 30mph are expected to sweep across Devon and Cornwall, while the Met Office has issued a red severe weather warning for parts of south east Wales.
In the face of drifting snow, the Met Office has warned people to avoid all but essential journeys.
Elsewhere in England, amber alerts have been in place for most of the week in the Midlands, London and the south, the east of England, the south west, the North West and Northern Ireland.
Gemma Plumb, a forecaster for Meteogroup, the weather division of the Press Association, said snowfall had been coming from all directions overnight.
Plumb said snow showers of 3 to 4cm in Suffolk, Essex, Norfolk and much of the east coast were to be expected.
Meanwhile, more persistent heavy snow was moving up in a band covering an area from the south west, across south west England, and including central and southern parts of Wales and central and southern England.
Plumb added that the winds in the south west and in Wales have created blizzards and that more snow would fall today, to add to the light dusting already received in much of the rest of England, Wales and southern Scotland.
Plumb said the Midlands and southern England, including London, would see between 5-10cm of snow on higher ground. However, she expects central and eastern Wales to be hardest hit.
In Devon and Cornwall, the snow is expected to turn to rain later in the day and will ease off elsewhere, remaining largely in eastern areas.
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