Video: The big scramble home as snow covers Yorkshire

Flights were cancelled at the country’s busiest airport while train companies axed rail services and roads were closed as the wintry conditions set in.

Motorists were urged to avoid all but essential journeys amid strong winds, plunging temperatures and the looming threat of blizzards.

Forecasts also forced hundreds of schools to shut their doors, meaning some sixth-form and college students saw their A-level exams postponed.

The adverse weather has already sparked panic-buying and left more than 10,000 people without electricity.

Weathermen predict around 12in (30cm) of snow will fall in some areas during the next few hours while gusts could reach galeforce of 40-45mph around Scottish isles.

Temperatures are expected to remain close to freezing throughout the day after dropping to -8 in the Highlands overnight.

The Met Office has issued a “red” severe weather warning for heavy snow in Wales, which is set to experience the worst of the snow.

Amber alerts were in place for the Midlands, London and the South, the east of England, the South West, the North West and Northern Ireland.

The arctic blast closed Cardiff airport this morning and led Heathrow to shut one runway for de-icing and snow-clearing, prompting delays and cancellations. The airport has already pulled around 70 flights.

A statement on Gatwick’s website warned passengers to check before leaving their homes.

Rail travellers also experienced upheaval as operators scrapped services.

Eurostar axed four trains between London and Brussels while South West Trains announced cancellations. The East Midlands, Greater Anglia and Southern companies were running amended timetables.

Poor conditions also caused severe hold-ups on the roads.

Cardiff city centre became a sludgy bumper-to-bumper convoy of commuters this morning as some braved the conditions while other usually busy routes were empty of cars.

The AA expected most disruption in Wales, the West Midlands, southern England and Northern Ireland.

Meanwhile, fears that householders would be snowed in prompted panic-buying which left shelves close to empty.

Frantic scenes were reported in stores across the West Country, Home Counties and south Wales as shops ran low on stock.

The snow brought misery to South Wales after a power cut left thousands of householders without electricity. Western Power said it was working to resolve the problem.

But the spectacular dusting of snow came as welcome news for thousands of children.

More than 1,200 schools closed across Wales, more than 500 turned youngsters away in Hampshire and some 300 cancelled classes in Norfolk.

Dozens more took similar action while many planned to send youngsters home early.

The move was cause for celebration among some A-level students whose exams were put back as colleges shut their doors.

Laura Caldwell, a forecaster for MeteoGroup, the weather division of the Press Association, said 4-6in (10-15cm) of snow would cover much of the country before easing off this evening.

“There’s going to be quite strong winds which will push the snow into drifts,” she added.

“Over the next 24 hours it is possible that 30cm or slightly more will fall in Wales.

“Winds will be near galeforce in coastal areas and it could gust up to galeforce around the Scottish isles, which traditionally get the worst winds.”

Forecasters have warned of blizzard conditions but said these would abate, with only light flurries expected tomorrow.

RAC spokesman Simon Williams said reaching stranded motorists was now a “real challenge”.

“We moved a number of our 4x4 patrols to help people stuck in the snow in West Wales and parts of Wiltshire, South Gloucestershire and Hampshire,” he said.

“In order to deal with an expected increase in calls for assistance later in the day, we have also put every technically qualified engineer normally based in the office back out on the road again in patrol vehicles.”

The RAC expects to be particularly busy in East Anglia.

Yesterday it attended around 3,000 more call-outs than usual.

Bristol Crown Court was closed today because of the adverse weather.

An A4 piece of white paper stuck to the court entrance with sticky tape bore a message in black capital letters stating: “Court Closed.

“Sorry but due to the weather it has been necessary to close this court.”

Not enough court staff could get to the building in Small Street, so the decision was taken not to open for the day’s cases.

The public has little sympathy for those who run public transport services affected by snow and icy conditions, a poll showed.

The majority of those surveyed (83%) said travel was too often disrupted by bad weather and most (90%) felt those who run trains, buses and airports should be better prepared, the ComRes poll for ITV News said.

School closures

Scarborough Sixth Form College and Woodlands School, Scarborough, are both closed today (Friday January 18, 2013).

In the East Riding, the following schools are closed or closing early: Hilderthorpe Primary, Hornsea School, Quay Primary School, South Holderness Technology College, Sproatley Primary School.