Power problems remain after severe weather cuts supplies
Engineers have been hampered by snow-drifts up to 18ft high in some parts as they try to restore power to thousands of UK homes hit by the severe weather.
Up to 10,000 properties in Scotland, 7,000 in Northern Ireland and more than 200 in west Cumbria are without power.
Some 6,000 north Wales homes have been reconnected over the weekend. An ice warning is in place for much of the UK.
Meanwhile, a 25-year-old whose body was found in snow on Saturday in Lancashire has been named as Gary Windle.
His body was found in deep snow in farmland near Burnley.
Police believe he had tried to walk home after a taxi had abandoned an attempt to drive him to Brierfield in severe weather on Friday night.
Lancashire villages in the area where his body was discovered were "running out of food" after being cut off, local police said.
Ch Insp Derry Crorken said police "simply cannot get to" villages near Burnley, including Brierfield, Wycoller and Briercliffe, to check on residents.
He said the force was working with Lancashire County Council to reach the villages and provide supplies.
A woman's body was found in the debris of her house after a landslip in Looe, Cornwall, early on Friday.
In a statement released on Sunday, the family of 68-year-old Susan Norman said: "As you imagine, the mood is rather numbing for Susan's family and friends at this sad time.
"We will get to the bottom of this potentially avoidable tragedy," it said. "The property's safety has been a concern of Susan's for some time as there have been two recent slips very close to [the] house."
Many roads blocked after snow on Friday and Saturday are still impassable.
As specialist rescue teams were deployed to help vulnerable people or those isolated in rural areas in Northern Ireland, one incident involved oxygen being airlifted to a 79-year-old man snowed in without electricity.
Ch Insp Tim Mairs said that some rescuers had walked for miles through heavy snow, facing "possibly 12 to 18ft drifts of snow" in some places, to reach housebound people.
The Met Office has issued a yellow "be aware" warning of ice for a large chunk of the UK from London in the south east, across north Wales up to Northern Ireland and across northern England and southern Scotland. The warning runs until 09:00 GMT on Monday.
The Met Office says existing snow in many areas will melt on roads and pavements by day, but refreeze by night to give icy patches.
Some places, mainly in eastern England, will continue to get light snow on Sunday, possibly up to a couple of inches.
Also, snow blowing off fields in strong-to-gale-force winds will affect some roads, especially over high ground, according to the Met Office.
In other developments:
- In north Wales, Scottish Power confirmed it had reconnected the last 500 homes that had still been without power on Sunday after being hampered by fallen trees blocking roads
- Northern Ireland Water says water supply has now been restored to most customers, after 1,000 were cut off on Saturday, but people in parts of County Antrim and north Down may experience low pressure or interruptions to supply
- Flights are operating again at Leeds Bradford Airport after earlier closures
- Flights at East Midlands Airport resumed at midday on Sunday after it had been shut by snow for several hours, with passengers advised to check with their airlines before travelling, or check the live information page
Northern Ireland Electricity said it could be "several more days" before all its customers were back on supply.
"Some roads are still impassable. Access has also been restricted because of drifting snow and abandoned vehicles," a spokeswoman said.
The situation has improved for many since Saturday morning, when 35,000 electricity customers were cut off.
Meanwhile, residents in parts of Arran fear they will remain off the national grid until Friday as areas of Scotland continue to be hit by the wintry weather.
About 2,000 homes on Arran, and 5,000 in Kintyre, have been without electricity since Friday.
Scottish and South Energy (SSE) said it hoped to return power to most homes on Arran and in the south of the Kintyre peninsula on Sunday.
But customers in more rural parts of both areas would still be without power overnight, the company warned.
About 500 workers are involved in the operation in the area, and SSE has ferried mobile generators to Arran and Campbeltown in Kintyre. It urged residents to conserve fuel supplies to help ease the burden on the generators.
About 2,000 properties in Dumfries and Galloway are also waiting to be reconnected following a weekend of snow, blizzards and heavy winds.
On Saturday, dozens of people had to be rescued on the A595, near Bootle in Cumbria, where people were forced to abandon their cars, with 37 given shelter at local hotels.
On Sunday, Cumbria Police appealed for any motorists who had abandoned their cars on the road to contact them by dialling 101.
They asked people not to return for their car until requested, "as there may be a significant delay and weather conditions are still challenging".
A spokeswoman added that some areas of the county were still being subjected to severe winds of up to 45mph, causing snow to drift on to the roads even as they were being cleared.
"This means that many of the roads are still blocked," she said, adding that in places drifts were up to 20ft high.
The cold weather comes as the UK prepares to switch its clocks on to British Summer Time next Sunday.
Forecasters have predicted that it could be the coldest March since 1962, when average temperatures for the month were 2.8C.