Police in England are carrying out a "rescue operation" to help people stranded in their vehicles across Somerset, including about 100 vehicles stuck in snow on the A303 at Ilminster.
A spokesman said: "This operation is being supported by a number of volunteers and voluntary agencies, including Avon and Somerset Search and Rescue, Exmoor Search and Rescue, Burnham Area Rescue Boat (which has 4x4 vehicles) and Wessex 4x4 Response, along with other emergency services and Her Majesty's Coastguard.
"If you are stranded, please stay in your vehicle, call for assistance and wait for help to arrive. Don't abandon your vehicle as it can hamper the efforts of emergency services."
Meanwhile, Hampshire Police said emergency services were continuing to deal with a "major incident" on the A31 after vehicles became stranded due to the severe weather conditions.
The force said they were unable to move the vehicles off the carriageway for "at least the next few hours", but were working to evacuate the most vulnerable people from the scene.
Assistant Chief Constable Dave Powell said: "All emergency services are working as hard as they can to get to as many people as possible at the scene and give them immediate assistance.
"I know that many people have been stuck for several hours and we are working as fast as we can to get to them, but at this stage we are limited to moving people from the scene rather than moving vehicles."
Those stuck on the road have been urged to call 101 if they have a medical condition or are running out of fuel, or to call 999 in an emergency.
The UK's South Central Ambulance Service NHS Foundation Trust has appealed for help from 4x4 owners to move its staff around in the adverse conditions, and dozens of volunteers have been battling through snow to take supplies to people stranded on the M62 motorway in Greater Manchester.
Drivers have been left trapped in their cars for several hours after heavy snowfall.
Eleanor Kelly, 19, said local residents in Milnrow, Rochdale, had been taking hot drinks, food and blankets to those stuck on the carriageway - including to a father with a baby and toddler in the car.
She said: "We've been trying to get to as many people as we can in about a mile radius from where we can get to the carriageway."
The local community centre, Butterworth Hall, was also opened to provide refuge for stranded motorists overnight.
Police say wind speeds over the Rakewood Viaduct in Greater Manchester have reached 90mph.
The North West Motorway Police tweeted: "J21-22 M62 the wind speeds over Rakewood are 90mph that is the reason vehicles cannot continue as it would be a risk to life."
Western Power Distribution figures showed around 4,000 properties in Wales and south west England had been left without power on Friday morning as a result of 38 incidents.
The UK's National Grid has withdrawn its gas deficit warning following an increase in supplies to the network as extreme weather continues to batter Britain.
The power operator said that following "significant supply losses" yesterday, the market has "continued to respond over the last 24 hours and we have seen an increase of supplies into the network".
"As the extremely cold weather continues we expect to see high demand on the gas network, so we are continuing to monitor developments closely," it added.
The military has been drafted to help hospitals and medics in the Midlands and West Country.
Devon and Cornwall NHS and Shropshire NHS have both asked for assistance, which began at 6am on Friday.
The Army has sent 10 4x4 vehicles and 20 troops to Shropshire while the Royal Marines have deployed the same resources in Devon and Cornwall.
Severe weather is causing continued disruption to travel in Scotland, with dozens of drivers stuck in a snowdrift.
Police said 20 to 30 vehicles became stuck in snow on the A92 near Inverbervie in Aberdeenshire shortly before 7am and efforts were underway to free them.
In Easter Ross, police said the Nigg, Fearn, Balintore, Portmahomack, Tain and Eddertson areas were closed off due to the adverse weather conditions, which are causing snowdrifts.
They were also dealing with incidents on the B9175 where some drivers were reportedly stuck during the night.
An amber weather warning for snow expires at 10am on Friday; however, a yellow warning of snow across Scotland is in place until 11.55pm on Saturday.
A number of rail and bus services in the amber alert area have been suspended throughout Friday morning over concerns for safety of staff and passengers.
Transport Minister Humza Yousaf said roads teams will need time to make routes safe even after the Met Office snow warning expires at 10am, and advised motorists to avoid travel.
He tweeted: "Please don't assume on Fri 10.01am that trunk road network will be completely clear. Gritters etc will need time for post Red/Amber recovery."
Troops have been called into transport medics to and from Edinburgh's two biggest hospitals after a request from NHS Lothian to the Scottish Government.
The extreme weather has seen health boards cancel non-essential operations and outpatient appointments on Friday, while NHS 24 has described its operations as being "stretched".
Princess Royal Maternity Hospital in Glasgow saw tiles fly from its roof under pressure from the extreme weather.
An estimated 1,000 vehicles were stuck on the M80 until Thursday afternoon, with some spending the night in their cars and others abandoning their vehicles on the motorway.
Other major roads such as the M876 and minor routes also faced severe disruption due to crashes and deep snow.
As difficult conditions are set to continue, flights at Scotland's busiest airports are facing another day of disruption and cancellations.
Glasgow and Edinburgh first called a halt to routes on Wednesday and will be reassessing safety during the morning.
Passengers have been warned to only travel to the airport once they have checked the status of their flight with the airline.
ScotRail has said no services will be running through the amber alert area until tests are carried out on tracks, while Virgin Trains has said its west coast route to Scotland could be closed and is eastern line will be limited.
A number of bus operators are also warning of disruption to routes on Friday morning, while Edinburgh Trams is running a reduced service.
Hundreds of schools up and down the country will remain closed, including in Glasgow, South Lanarkshire, East Lothian, West Lothian and Edinburgh.
Glasgow School of Art has also been closed until Monday.
Witnesses due at 15 courts in Scotland have been told not to attend after trials were cancelled over safety fears.
Courts affected include Glasgow, Edinburgh, Livingston, Kirkcaldy, Dunfermline, Hamilton, Alloa, Stirling, Falkirk, Paisley, Dumbarton, Airdrie, Greenock, Perth and Coatbridge.