Dozens of vehicles have been stranded on the A30 dual carriageway in Devon amid heavy snow.
The wintry showers which disrupted many parts of the UK over the weekend have largely stopped but a Met Office amber warning remained in place in south-west England until the early hours.
The car park of a service station in Okehampton is full with drivers bedding down for the night in their vehicles.
About 40 people – including 15 children – are staying at the town’s college.
Forecasters say about 5cm of snow could fall at lower levels across the South West, with as much as 30cm in places across Dartmoor and Exmoor.
Devon and Cornwall Police say the A30 from the M5 at Exeter to near Bodmin in Cornwall is currently closed because of the conditions.
The force tweeted: “Drivers are warned to expect snow and icy conditions on morning commute. Only travel if you have to and leave extra time for your journey.”
Scores of schools in Devon will be closed on Monday.
Earlier on Sunday, two multi-vehicle crashes caused long delays on the A30 around Okehampton and Whiddon Down.
Elsewhere, ice resulted in delays and cancellations at Gatwick Airport on Sunday night.
The airport apologised to affected passengers, saying the problems were “due to the prolonged cold snap and the essential de-icing requirements which have mounted during the afternoon and evening”.
Temperatures were expected to fall below freezing across many parts of the UK overnight, causing partly melted snow to refreeze.
A Met Office yellow warning for ice is in place for most of England and Wales, central and southern Scotland and parts of Northern Ireland until 10:00 GMT.
Forecasters say more normal, spring-like conditions are likely to return to most areas by Tuesday.