Travel across much of the UK has been made treacherous due to freezing temperatures and heavy snowfall.
Several road closures are in force, while trains and flights have been hit by delays and cancellations.
Here are some of the latest reported issues.
In Scotland, 300 motorists remained stuck on the M80. Around 1,000 were there overnight as heavy snow fell. The motorway was closed southbound between junctions 8 and 9.
Police Scotland warned people not to travel unless they were an emergency worker.
Lincolnshire Police warned overnight that the A52 was "impassable" between Boston and Skegness due to drifting snow, and warned that drivers faced becoming stranded.
"We are not in a position to recover you," the force tweeted.
The fire and rescue service added that even a snowplough was unable to get through to clear the route.
Several other roads in Lincolnshire have also been shut, including the A17 and the A15 between the M180 and Lincoln.
Cheshire Police said there were around eight miles of tailbacks on the M62 as officers with 4x4s, Highways England patrols, contractors and snowploughs attempted to clear snow between junctions 21 and 22 eastbound.
By 8.30am on Thursday morning the AA said it had already answered calls from more than 100 drivers stuck in snow, with East Anglia and the North East the worst-hit regions.
AA president Edmund King compared driving on many "atrocious" UK roads to skating on ice rinks, and said they had added extra patrols and 4x4s to cope with the severe conditions.
The A66 in Cumbria was closed in both directions between Scotch Corner and Brough, due to "severe snowfall", while the A56 in Lancashire was likely to be closed for "several hours" due to a lorry crash between the M65 and A680.
Northumbria Police said the A68 was closed between Corbridge and Ridsdale.
In Derbyshire, the Woodhead Pass was shut in both directions between Tintwistle and Flouch.
Nearly all train operators across the UK are suffering cancellations and disruption on Thursday.
All cross-border trains between England and Scotland were suspended.
The West Coast Main Line was closed until at least midday between Carlisle and Scotland, with no trains or replacement buses.
Virgin Trains East Coast asked passengers "not to travel" on Thursday or Friday across the entire East Coast Main Line between London and Scotland.
ScotRail halted all operations in the affected red area until late morning.
London Paddington, the UK's seventh busiest station, was closed at 8am. Long distance services are starting and terminating at Reading.
Around 50 stations in Kent and East Sussex were closed on Thursday as operator Southeastern advised commuters to work from home if possible.
Northern said the severe weather had left several routes blocked, with delays and cancellations across the whole network.
Airports have been severely affected by the conditions, with hundreds of flights cancelled.
Heathrow was badly hit, with airlines forced to reduce schedules on Thursday and Friday following discussions with airport officials and air traffic control provider Nats.
British Airways cancelled more than 180 flights, affecting long haul and short haul routes.
Other airlines to cancel flights at the west London hub include Virgin Atlantic, Lufthansa and Flybe.
A total of at least 76 flights serving London City Airport were cancelled on Thursday.
The closure of Glasgow Airport was extended until at least 3pm due to further heavy snow showers.
Edinburgh Airport tweeted that most airlines had cancelled services until lunchtime.
There were cancellations and delays at Gatwick Airport.
The runway at East Midlands Airport was temporarily closed on Thursday morning, and travellers were warned it could affect flights.