Heavy snow has brought widespread chaos across Wales.

More than 1,200 schools have closed, 10,000 people are without electricity and transport is being disrupted.

snow

Footprints in the snow covered streets of Llanelli, Wales

Problems surfaced yesterday after the Met Office issued a "rare" red warning of snow for the south-eastern side of the Brecon Beacons and Black Mountains - and warned that all non-essential travel should be avoided.

This morning large swathes of the principality woke up to find a dusting of snow outside.

But while many children rejoiced at getting a day off school, the day began with a travel problems for adults.

The M4 was initially closed by police in both directions between junctions 36 and 37 at Bridgend - resulting in bumper-to-bumper traffic as motorists tried in vain to steer clear of the area.

Even when the motorway reopened, traffic was still moving slowly due to lane closures.

Meanwhile, all schools in Neath Port Talbot were closed and the majority in Swansea and Torfaen were shut.

The closures meant that some sixth form and college students had their A-level exams postponed.

The snow also hit flights at Cardiff International Airport and cases at Cardiff Crown Court were adjourned for the day.

Some people in South Wales who may have relished the prospect of a duvet day were also in for disappointment when a power cut left thousands of householders without electricity.

Western Power said it was working to resolve the problem and asked customers to call its emergency line on 0800 052 0400 if they are in difficulties.

Spokesman Phil Davies said: "The advice is to sit tight. If you are in any difficulty, ring our emergency line. We will provide as much help as we can.

"If anybody has a particular difficulty we will do our utmost to get to them and get them back on supply."

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  • Winter weather Jan 25

    A man uses a tractor as he tries to try and keep the roads open in Tanfield, Durham as more snows falls in the UK.

  • Winter weather Jan 25

    A woman digs her way out after more snow falls today in Tanfield County, Durham.

  • Winter weather Jan 25

    A woman digs her way out after more snow falls today in Tanfield County, Durham.

  • Winter weather Jan 25

    A man uses a tractor as he tries to try and keep the roads open in Tanfield, Durham as more snows falls in the UK.

  • Winter weather Jan 25

    A woman digs her way out after more snow falls today in Tanfield County, Durham.

  • Winter weather Jan 25

    A woman digs her way out after more snow falls today in Tanfield County, Durham.

  • Winter weather Jan 25

    Two woman battle through the snow after more snow falls today in Tanfield County Durham.

  • Winter weather Jan 25

    A man shovels snow after more snow falls today in Tanfield County Durham.

  • Winter weather Jan 25

    A woman digs her way out after more snow falls today in Tanfield County, Durham.

  • Winter weather - Jan 22nd

    A man struggles in the snow as he walks past the starters box on the PGA Centenary Course after more snowfall today at Gleneagles Hotel in Perthshire. The course will be used for the 2014 Ryder Cup.

  • Winter weather - Jan 22nd

    A road traffic sign covered in snow and ice at Spring Cottage, Derbyshire as the winter weather continues across the UK.

  • Winter weather - Jan 22nd

    People struggle in the snow with shovels on a golf course at Gleneagles after more snowfall today in Perthshire.

  • Winter weather - Jan 22nd

    A man struggles in the snow as he walks past the starters box on the PGA Centenary Course after more snowfall today at Gleneagles Hotel in Perthshire. The course will be used for the 2014 Ryder Cup.

  • Winter weather - Jan 22nd

    A man walks his dog near Auchterarder, Perthshire after heavy snowfall overnight.

  • Winter weather - Jan 22nd

    Loggers Trucks collect trees in Kielder Forest, Northumberland where snow fell overnight.

  • Winter weather - Jan 22nd

    Snow and ice cover barges and boats at Foxton Locks in Market Harborough, Leicestershire as the winter weather continues across the UK

  • Winter weather - Jan 22nd

    General view of a street in Pricetown, Dartmoor, as snow starts to fall again.

  • Winter weather - Jan 22nd

    Don Clegg, 80, clears snow from his drive in Kielder, Northumberland as the winter weather continues across the UK.

  • Winter weather - Jan 22nd

    Loggers Trucks battle up the hill in Kielder Forest, Northumberland where snow fell overnight.

  • Winter weather - Jan 22nd

    A man fits snow chains to his car in preparation for driving in hazardous conditions as the winter weather continues across the UK.

  • Winter weather - Jan 22nd

    Don Clegg, 80, in his garden in Kielder, Northumberland as the winter weather continues across the UK.

  • Winter weather - Jan 22nd

    Loggers Trucks collect trees in Kielder Forest, Northumberland where snow fell overnight.

  • Winter weather - Jan 22nd

    Loggers Trucks collect trees in Kielder Forest, Northumberland where snow fell overnight.

  • Winter weather - Jan 22nd

    Mum Stephanie Koch (right) and daughter Kadie 4 enjoy the snow in Kielder, Northumberland as the winter weather continues across the UK.

  • Winter weather - Jan 22nd

    Dogs walking in Innerleithen, the Scottish Borders as snow showers hit the East of Scotland.

  • Winter weather - Jan 22nd

    A car sets off down a snow covered road in the Borders as snow showers hit the East of Scotland.

  • Winter weather - Jan 22nd

    A snow covered road in Galashiels the Scottish Borders as snow showers hit the East of Scotland.

  • Winter weather - Jan 22nd

    A horse runs along a snow covered field in the Borders as snow showers hit the East of Scotland.

  • Winter weather - Jan 22nd

    Sheep look for food in the Scottish Borders as snow showers hit the East of Scotland.

  • Winter weather - Jan 22nd

    A snow covered road in Galashiels the Scottish Borders as snow showers hit the East of Scotland.

  • Winter weather - Jan 22nd

    A car sets off down a snow covered road in the Borders as snow showers hit the East of Scotland.

  • Winter weather - Jan 22nd

    Mum Stephanie Koch (right) and daughter Kadie 4 enjoy the snow in Kielder, Northumberland as the winter weather continues across the UK.

  • Winter weather - Jan 22nd

    Snow and ice cover Foxton Locks in Market Harborough, Leicestershire as the winter weather continues across the UK

  • Winter weather - Jan 22nd

    Snow and ice cover Foxton Locks in Market Harborough, Leicestershire as the winter weather continues across the UK

  • BRITAIN-WEATHER-SNOW

    A woman walks a dog through a snow covered Rose Garden at The Arno in Birkenhead, northwest England, on January 21, 2013. Britain is braced for a continuation of the bad weather which has left closed schools and caused transport chaos in recent days, with several weather warnings in place. AFP PHOTO / PAUL ELLIS (Photo credit should read PAUL ELLIS/AFP/Getty Images)

  • UK Hit By Heavy Snow Fall

    NOTTINGHAM, UNITED KINGDOM - JANUARY 21: Freddy the Boston Terrier plays in the snow on January 21, 2013 in Nottingham, United Kingdom. The United Kingdom has suffered a weekend of heavy snowfall with many transport routes affected. (Photo by Laurence Griffiths/Getty Images)

  • UK Hit By Heavy Snow Fall

    NOTTINGHAM, UNITED KINGDOM - JANUARY 21: Canada Geese fly from the snow covered banks of the River Trent on January 21, 2013 in Nottingham, United Kingdom. The United Kingdom has suffered a weekend of heavy snowfall with many transport routes affected. (Photo by Laurence Griffiths/Getty Images)

  • UK Hit By Heavy Snow Fall

    NOTTINGHAM, UNITED KINGDOM - JANUARY 21: Wild birds feed on the snow covered banks of the River Trent on January 21, 2013 in Nottingham, United Kingdom. The United Kingdom has suffered a weekend of heavy snowfall with many transport routes affected. (Photo by Laurence Griffiths/Getty Images)

  • UK Hit By Heavy Snow Fall

    LONDON, UNITED KINGDOM - JANUARY 21: A snowman complete with cigarette and coffee cup is viewed by a squirrel in St James's Park on January 21, 2013 in London, England. The United Kingdom has suffered a weekend of heavy snowfall with many transport routes affected. (Photo by Peter Macdiarmid/Getty Images)

  • UK Hit By Heavy Snow Fall

    NOTTINGHAM, UNITED KINGDOM - JANUARY 21: Canada Geese fly from the snow covered banks of the River Trent on January 21, 2013 in Nottingham, United Kingdom. The United Kingdom has suffered a weekend of heavy snowfall with many transport routes affected. (Photo by Laurence Griffiths/Getty Images)

  • UK Hit By Heavy Snow Fall

    LONDON, UNITED KINGDOM - JANUARY 21: A woman walks on Birdcage Walk as snow falls on January 21, 2013 in London, England. The United Kingdom has suffered a weekend of heavy snowfall with many transport routes affected. (Photo by Peter Macdiarmid/Getty Images)

  • BRITAIN-WEATHER-SNOW

    Models pose around a plastic palm tree in the snow in front of Tower Bridge in central London on January 21, 2013, during a 'pop-up beach resort' promotion on the day that many consider to be the most depressing day of the year. Britain is braced for a continuation of the bad weather which has schools closed and caused transport chaos in recent days, with several weather warnings in place. AFP PHOTO / CARL COURT (Photo credit should read CARL COURT/AFP/Getty Images)

  • BRITAIN-WEATHER-SNOW

    A woman walks a dog through a snow covered Rose Garden at The Arno in Birkenhead, northwest England, on January 21, 2013. Britain is braced for a continuation of the bad weather which has left closed schools and caused transport chaos in recent days, with several weather warnings in place. AFP PHOTO / PAUL ELLIS (Photo credit should read PAUL ELLIS/AFP/Getty Images)

  • BRITAIN-WEATHER-SNOW

    People walk a dog through a snow covered Arrowe Park in Birkenhead, northwest England, on January 21, 2013. Britain is braced for a continuation of the bad weather which has left closed schools and caused transport chaos in recent days, with several weather warnings in place. AFP PHOTO / PAUL ELLIS (Photo credit should read PAUL ELLIS/AFP/Getty Images)

  • BRITAIN-WEATHER-SNOW

    A woman walks a dog through a snow covered Rose Garden at The Arno in Birkenhead, northwest England, on January 21, 2013. Britain is braced for a continuation of the bad weather which has left closed schools and caused transport chaos in recent days, with several weather warnings in place. AFP PHOTO / PAUL ELLIS (Photo credit should read PAUL ELLIS/AFP/Getty Images)

  • UK Hit By Heavy Snow Fall

    NOTTINGHAM, UNITED KINGDOM - JANUARY 21: Canada Geese fly past the snow covered banks of the River Trent on January 21, 2013 in Nottingham, United Kingdom. The United Kingdom has suffered a weekend of heavy snowfall with many transport routes affected. (Photo by Laurence Griffiths/Getty Images)

  • UK Hit By Heavy Snow Fall

    LONDON, UNITED KINGDOM - JANUARY 21: A man walks on The Blue Bridge over the partially frozen lake in St James's Park on January 21, 2013 in London, England. The United Kingdom has suffered a weekend of heavy snowfall with many transport routes affected. (Photo by Peter Macdiarmid/Getty Images)

  • BRITAIN-WEATHER-SNOW

    People walk a dog through a snow covered Arrowe Park in Birkenhead, northwest England, on January 21, 2013. Britain is braced for a continuation of the bad weather which has left closed schools and caused transport chaos in recent days, with several weather warnings in place. AFP PHOTO / PAUL ELLIS (Photo credit should read PAUL ELLIS/AFP/Getty Images)

  • BRITAIN-WEATHER-SNOW

    Models in swimwear pose in the snow at a 'pop-up beach resort' promotion in front of Tower Bridge in central London on January 21, 2013. Britain is braced for a continuation of the bad weather which has schools closed and caused transport chaos in recent days, with several weather warnings in place. AFP PHOTO / CARL COURT (Photo credit should read CARL COURT/AFP/Getty Images)

  • UK Hit By Heavy Snow Fall

    LONDON, UNITED KINGDOM - JANUARY 21: Pigeons look for food in a snowy St James's Park on January 21, 2013 in London, England. The United Kingdom has suffered a weekend of heavy snowfall with many transport routes affected. (Photo by Peter Macdiarmid/Getty Images)

  • UK Hit By Heavy Snow Fall

    LONDON, UNITED KINGDOM - JANUARY 21: Pigeons try to keep out of the snow by resting on a signpost in St James's Park on January 21, 2013 in London, England. The United Kingdom has suffered a weekend of heavy snowfall with many transport routes affected. (Photo by Peter Macdiarmid/Getty Images)