More snowfall across parts of the UK has brought fresh travel disruption and school closures to thousands.
There are several severe weather warnings in place and councils say they are running low on gritting salt.
The AA warned shortages of salt have created a "road safety crisis", but the government said it was difficult to prepare for such unusual weather.
The M4, M5 and M1 have been badly affected and hundreds of schools have been forced to close their doors.
The Met Office has issued a number of severe weather warnings for heavy snow in much of southern and central England, Scotland and Northern Ireland.
Some 20cm (7.9in) of snow has been reported in parts of the Cotswolds and Aberdeenshire.
Cotswolds: 7.9in (20cm)
Salisbury Plains: 4.7in (12cm)
Oxfordshire: 3.9in (10cm)
Leicestershire: 3.9in (10cm)
Antrim Hills, Northern Ireland: 3.9in (10cm)
Chilterns: 3.9in (10cm)
Bristol: 3.9in (10cm)
Midlands: 4.7in (12cm)
Source: BBC Weather Centre, 1300 GMT
Matt Taylor of the BBC Weather Centre said the snowy weather would start to ease for much of the UK through the night but with widespread icy conditions developing.
By Friday morning, parts of central and southern England would receive the next heavy snowfall, he added.
Some councils have just three days' worth of grit left after supplies were "massively" depleted by the heavy snow, the Local Government Association (LGA) admitted. Worcestershire County Council is not gritting roads but sending out snow ploughs.
Country Councils in Warwickshire, Wiltshire, Gloucestershire and Ceredigion as well as Swindon borough council have confirmed that they are running low on salt and are only salting main routes.
Hertfordshire County Council said it was seeking additional supplies from abroad, while Cumbria County Council said it could over-spend its winter maintenance budget by £1.3m.
Derek Turner, Director of Networks Operations at the Highways Agency, said it had "three, four days of salt supplies remaining".
Travel disruption across the country has included:
The M4 was the worst-affected route with much of the snow lying and lanes closed. Conditions on the M5 around Birmingham are reported to be deteriorating, and the M1, M3, M11 and M40 are also affected. Lorry drivers have been urged to stay off the roads in Northamptonshire
A convoy system is being operated on the A9 between Aviemore and Inverness, and Grampian Police advised drivers they should only venture out on essential journeys in the Moray area
The National Rail Enquiries website is reporting disruption to First Great Western and London Midland services
There are at least 10 cancellations on the National Express East Coast line and more on Virgin Trains between London Euston and Birmingham
Trains are not running on the Severn Beach line near Bristol and First, Wessex and South Gloucestershire bus services are also currently suspended around the city
A vehicle negotiates heavy snow in Duston, Northamptonshire
Arriva bus services are suspended in Aylesbury, Stevenage, Hemel Hempstead, Milton Keynes and Luton
The runways at Aberdeen, Luton, and Robin Hood International airports have been closed. Birmingham, East Midlands, Cardiff Wales and George Best Belfast City airports have reopened, but flights have been delayed.
At Luton, check-in has been suspended and flights are subject to delay and cancellation. Bristol Airport is open but experiencing delays.
Thousands of pupils have had another day off as schools across the UK closed their doors on Thursday.
Some 623 in Wales have shut, while other closures have been reported in Aberdeenshire, Moray, Birmingham, Bedfordshire, Buckinghamshire, Cambridgeshire, Sheffield, Rotherham, Coventry, Warwickshire, Hertfordshire, and Oxfordshire.
Devon, Bristol, Shropshire, Somerset, Lincolnshire, Leicestershire, Northamptonshire, Solihull, Worcestershire, Herefordshire, Staffordshire, Cheshire and Norfolk have also reported school closures.
A walker has died after falling over 100 feet in icy conditions in the Lake District.
Two missing climbers in the Cairngorms have been found safe and well. The two men - thought to be from the Inverness area and aged 22 and 29 - were spotted by a rescue helicopter from RAF Kinloss and have been flown to safety.
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