Snow hits UK schools and transport A van slips in the snow on the A367 between Bath and Peasedown St John in south-west England. There was misery for travellers but joy for children across swaths of Britain as up to 30cm of snow caused transport chaos and led to the shutting of more than 1,000 schools. The areas worst hit on Friday morning included much of south Wales, where a rare "red" severe weather warning was issued, much of the south-west of England and parts of the Midlands. But there were also heavy falls across some areas of eastern England, including Essex, Suffolk and Norfolk. Some stretches of motorways were closed and many A-roads impassable. There were dozens of accidents, many involving lorries that had jack-knifed in the icy conditions. Hundreds of motorists attempted to get out only to get stuck and abandon their vehicles, causing further chaos. Airports were hit, with Heathrow closing its north runway temporarily to clear snow. A Heathrow spokeswoman said 170 flights had been cancelled by late morning, while Southampton's airport was expected to be closed until at least 3pm. Scores of bus and train services were also disrupted. In some parts of Wales householders reported power blackouts and the loss of phone contact. Western Power Distribution said 10,000 customers were without power. Some hospitals cancelled routine operations. The snow began falling in many parts in the early hours and by daylight there was a covering of 10cm in many areas. Winds of up to 40mph caused the snow to drift to up to 30cm. Forecasters at the Met Office had seen it coming. They issued a "red" severe warning for south Wales and an "amber" one for other parts of Wales, western England, the Midlands and central and southern England, as well as Northern Ireland. The red warning means people should take action to keep themselves and others safe from the impacts of the weather. Snow was expected to spread further east, including London, during the morning and possibly turn to rain in some areas of the far west. But the temperature was likely to remain sub-zero in many parts of the country and more snow could follow over the weekend. Travel organisations were facing a difficult day. Gritters were out in force, and the Highways Agency issued an amber alert, advising motorists to take extra care and check weather forecasts before they travelled. Steve Crosthwaite, head of the Highways Agency's national traffic operations centre, urged drivers to allow more time for morning travel. He said: "During periods of severe weather we also suggest people consider whether their journey is essential." Among the early problem spots was the M4 near Bridgend in south Wales where the motorway was shut in both directions. The diversion route was also blocked. Part of the M50 in Herefordshire was also shut. Most routes into London were clear for the morning commute - but could be trickier this afternoon and evening. In Scotland, a section of the A821 in Stirling was closed due to snow. Anticipating the snow, some train companies had planned reduced services. Southern, Greater Anglia, South West Trains and the Eurostar were all running amended services on a number of routes or with speed restrictions because of the snow. Airports where flights were disrupted included Cardiff, Norwich, Southampton and Jersey. Many hundreds of schools were shut across the country - including more than 1,000 in Wales and 400 in Hampshire and the Isle of Wight. The Welsh local government and communities minister, Carl Sargeant, urged people to check their neighbours were well. He said: "I would also ask people to consider if family members or neighbours in their community need help. Have their phone numbers to hand and stop by to offer help with grocery shopping or other essential tasks - it can make a real difference. Cardiff and Vale University health board cancelled all routine outpatient clinics at both the University Hospital of Wales and University Hospital Llandough. Urgent outpatient services including acute renal, acute paediatric and acute oncology clinics were going ahead. The board's deputy chief executive, Paul Hollard, said: "We have unfortunately had to make the decision to suspend the majority of our outpatient clinics today so that we can prioritise the use of our staff to those patients who are currently in hospital and managing emergency cases. We would ask patients who were due to be seen in outpatients today not to ring in to our hospitals as the switchboard is dealing with urgent and emergency calls.