Britain shivers in snow's icy grip Ice hangs from fountains in Trafalgar Square, London. Photograph: Paul Brown/Rex Features Snowfall and freezing temperatures have settled in for at least a week across the UK with serious travel disruption likely for another day, particularly in the north-east of England. Heathrow airport expects to cancel at least 10% of scheduled flights, with those due to take off after 4pm most vulnerable because reduced visibility is forcing longer delays between takeoffs and landings at one of the world's busiest airports. The number of flights affected is likely to be half the 260 cancelled on Sunday when the airport's travails were reflected elsewhere in Europe, including Paris Charles de Gaulle, which lost 40% of its flights. There were also problems at Frankfurt, Geneva and Munich, which are all used to severe wintry conditions. National Rail has warned of problems across the country, with buses replacing trains between Brighton and Three Bridges on Southern and delays on the east coast mainline, the Gatwick Express and between Birmingham and Wolverhampton where signalling difficulties have added to the effects of the weather. Eurostar, First Capital Connect, London Overground, Southeastern, Southern, South West Trains and Virgin all warned of amended timetables and asked passengers to check in advance. The Highways Agency said the M40 southbound was closed by an accident between the M42 south of Birmingham and junction 16. In the Pennines, where there is expected to be further heavy snowfall, the A628 Woodhead Pass and the A66 across the moors between Bowes in County Durham and Brough in Cumbria are both shut and likely to remain so for much of Monday. The Environment Agency has two flood warnings in the south-west along the Winterbourne valley and at North Curry, and 34 alerts, with a further 16 alerts in the south-east, three in the Anglia region and one each in the north-east and Wales. A driver was killed in a weather-related accident on the A12 in Essex on Sunday night and a teenager is seriously ill with head injuries in the James Cook University hospital at Middlesbrough after a sledging accident. A man was treated in hospital after being attacked by teenagers who were pelting him with snowballs in what police are treating as a racially motivated incident. The Met Office said conditions would remain cold and cloudy for most of the country with occasional glimpses of sun. The main snowfall is expected in inland areas of the north-east with a bitter wind causing drifts. Northern Ireland can also expect lighter falls and sleet, and snow will return to the south later in the day. There is likely to be little letup overnight with a fresh band of rain, sleet and snow moving into the south-west from the Atlantic but conditions show signs of settling down and becoming drier late on Tuesday. The forecast for later in the week says: "Cold but generally more settled than earlier. Still a few snow flurries Wednesday, but dry and brighter for many on Thursday. Turning wet and windy in the north-west on Friday. Many southern and central regions are likely to start dry on Friday but generally rather cloudy. However, more unsettled conditions with spells of rain, sleet and snow along with increasing winds will develop over north-western parts. The unsettled conditions are then expected to spread erratically south-eastwards over the weekend. Remaining cold initially, with hard overnight frosts, widespread ice and some freezing fog patches, these will be locally slow to clear from some areas. However, during the weekend and into the new working week onwards, conditions are likely to turn rather less cold, as more unsettled Atlantic weather systems push into the UK. Heathrow airport has spent £36m on improving snow equipment since 2010 when it was forced to close shortly before Christmas, but a spokesman said that sheer busyness made a reduction in flights inescapable. He said: "Many airports have plenty of spare runway capacity so aircraft can be spaced out more during low visibility without causing delays and cancellations. But because Heathrow operates at almost full capacity, there is simply no room to reschedule the delayed flights. Friends have paid tribute to three young climbers who died in an avalanche near Glencoe with a fourth person in their party who has not yet been named. Junior doctor Una Finnegan and PhD students Christopher Bell and Tom Chesters were swept more than 1,000 feet down Bidean Nam Bian at the weekend. The fourth victim was a young woman. The fifth member of the party, a 24-year-old woman, is in a critical condition in hospital. The last member of the group managed to leap out of the way and cling to an ice axe, escaping uninjured. The two men were highly experienced climbers - Chesters, 28, was one of the UK's leading competitive orienteerers while Bell, 24, was a national-level triathlete. Bell was from Blackpool and studying at Oban for a doctorate in ocean mapping while Chesters was living in Leeds and studying at Hull University. Sam Morris, 35, a friend of both men and who worked with them guiding mountain bikers in the Alps, said: "It was so few years lived but I know there's not much either one of them would have done differently. They seized every opportunity. They'd do things that people who spend their whole lives sitting behind a desk wish they could have done. When they died they were with the people they loved, doing what they loved. Finnegan, 25, was originally from Coleraine in County Derry, where her father Dr Owen Finnegan was a respected consultant at Causeway hospital. She studied at Newcastle and Edinburgh and lived in the Scottish capital. A friend of the family, David McClarty, said: "When one hears of a tragedy like this your heart goes out to the families affected, but when you discover that one of them is your own it brings it home to you much worse. This young woman, a qualified doctor, had her whole life ahead of her and then it is tragically cut short. The family is a Christian one and hopefully they will get some comfort from the fact that she died doing something she enjoyed.