Brits could wake up to snow as the Arctic blast grips the country for up to a week amid fears over travel issues and power cuts as temperatures are predicted to drop to as low as -10C.
The Met Office has issued a yellow weather warning for heavy snow along parts of the east coast of England including Norfolk, East and North Yorkshire, Tyne and Wear, Lincolnshire, Durham and Northumberland.
The weather warning runs between 5pm and 11.59pm on Saturday, with between one and three cm of snow forecast.
It is thought that roads and railways could be affected with longer journey times, and there could be icy patches on roads.
Travel chaos has already begun, with one dramatic video on Friday showing a car colliding with another vehicle after the driver lost control on thick ice in a country road, near Ivinghoe in Buckinghamshire.
National Rail warned passengers to check before they travel, while ScotRail could not run trains to and from Thurso in the Highlands because of heavy snow, with replacement buses also not possible because of road conditions.
The operator advised passengers in the area to 'postpone travel where possible as we may not be able to guarantee you are able to complete your journey'.
A Gritter lorry on the A9, south of Inverness, attempts to tackle the piling snow on the road
Snow covers the hills in Llangollen, Wales, as arctic air from Scandinavia moves across the UK
A child builds a snowman in the snow in Ballater, Scotland, where amber warning are forecast
Snow has been falling since New Year's Day in Scotland but significant accumulations are building up there after an amber warning came into force at midday on Friday.
Two separate amber warnings for heavy snow in part of the Highlands and north-east Scotland were issued, while a yellow warning of snow and ice covered the country as far south as Angus and Perthshire.
The alerts warn of between 10 to 20cm of snow at low levels, with between 30 to 40cm possible on high ground.
It is thought there will be further delays and possible cancellations to rail and air travel, as well as power cuts, which could isolate some rural communities.
Hazardous driving conditions have already been reported near Glencoe, while Highland Council said it had received reports of campervans and cars stuck on ice in tourist hotspots.
Daytime temperatures across the UK are expected to struggle to go over 0C in the coming days.
Met Office chief meteorologist Rebekah Hicks said: 'Arctic air and brisk northerly winds are gripping the UK as we start the new year.
'Snow and ice warnings remain in force for many areas, with the risk of heavy snow showers, especially across northern Scotland and over higher ground elsewhere, though many inland areas will stay largely sunny and clear.
'Bitterly cold conditions will persist through the weekend and into next week, with daytime temperatures struggling to rise above freezing for some, and overnight lows dipping to minus double figures in places.'
One dramatic video today showed a car colliding with another vehicle after the driver lost control on thick ice in a country road near Ivinghoe in Buckinghamshire
A snow plough attempts to make the roads safety amid plunging temperatures in Scotland
Traffic built up on the A9, south of Inverness, amid falling snow and worsening conditions
Snow covers roads and cars on a residential street in Aberdeen, Scotland
People were even able to ice skate on Loch Morlich in Aviemore on Friday
A man takes to the street to clear up snow amid the amber weather warning being issued
People sledging in Loch Morlich, Aviemore, after amber weather warnings were issued
People wrapped up against the cold weather to take a walk through the snow in Scotland
Dog walkers in the snow in the Aberdeenshire town of Stonehaven on Friday afternoon
Snow falls on the A41 near Tring in Hertfordshire in the early hours of Friday morning
Snow in the village of Tatsfield in Surrey on Friday morning as weather warnings are imposed
As a result, the UK Health Security Agency (UKHSA) extended an amber cold health alert for all of England until next Friday (January 9) mid warnings of the weather causing a rise in deaths.
Health Secretary Wes Streeting warned that the 'bitingly cold snap' will put extra pressure on NHS hospitals as he urged people to only attend A&E for emergencies.
Mr Streeting said: 'In spite of all of the challenges the NHS faces this winter, the Herculean efforts of NHS staff and our investment and modernisation mean that hospital bed occupancy is lower than this time last year and ambulance handover performance is improving.
'But we still face intense pressures, and with this bitingly cold snap adding additional challenges, it is more vital than ever those eligible get their flu jab and people only attend A&E in an emergency.
'Let's all join NHS staff in doing everything we can to protect ourselves and our families through a difficult winter so NHS services are free for those who really need them.'
Data shows there can be a rise in heart attacks, strokes and respiratory illnesses during a cold snap, with older people and those with long-term health conditions most at risk.
There is also an increased risk of trips and falls in icy and cold weather, which can lead to serious injuries and more people attending A&E or needing help via other NHS services.
People walk through a snow-covered Burton Dassett Hills Country Park amid the cold weather
Waves crash against the sea wall in Whitley Bay, North Tyneside, amid weather warnings
A child sledges down snowy hills at Burton Dassett Hills Country Park in Warwickshire
People walking in the snow around Dinas Bran Castle in Llangollen, North Wales, on Friday
Snow in the village of Tatsfield in Surrey on Friday morning as weather warnings were imposed
Snow-covered fields in the village of Bishop's Itchington in Warwickshire on Friday
Snow-covered houses in the village of Bishop's Itchington in Warwickshire on Friday morning
Snow in the village of Tatsfield in Surrey on Friday morning amid amber weather warnings
Vehicles after a collision on a road near Burton Dassett Hills Country Park, Warwickshire
Dr Paul Coleman, consultant in health protection at the UKHSA, said: 'The weather is forecast to be very cold across England over the coming few days.
'Low temperatures like these can have serious impacts on the health of some people, particularly older people and those with serious health conditions.
'Exposure to cold can lead to increased risk of heart attacks, strokes and chest infections.
'It is therefore really important, as the colder weather sets in, to check in on friends, family and neighbours that are most vulnerable.'
The British Heart Foundation said cold weather can present specific risks for people with heart conditions because the heart has to work harder which can exacerbate existing health conditions.
The organisation said there are thousands of additional deaths from heart and circulatory disease in the winter months every year in the UK.
Ruth Goss, senior cardiac nurse at the British Heart Foundation, said: 'Cold temperatures can increase the risk of heart attacks and strokes, and people with cardiovascular disease are also more at risk of serious illness if they get seasonal respiratory infections like flu.
'It's especially important that people living with heart conditions are well prepared for the cold snap this winter by wrapping up warm and having their free flu jab.'
People skiing at the Cairngorm Ski Centre in the Scottish Highlands on Friday afternoon
Snow on the ground surrounding the Horseshoe Pass in Denbighshire, North Wales
People sledging at Loch Morlich in Aviemore in the Scottish Highlands on Friday afternoon
People walk through a snow-covered Burton Dassett Hills Country Park in Warwickshire
People wrap up against the cold in Westminster today as temperatures drop below freezing
Strong waves hit the North East coast at Seaham in County Durham on Friday morning
A major rescue operation was launched at Withernsea on the East Yorkshire coast
HM Coastguard deployed a helicopter to the scene after people got into difficulty in the water
The major operation was attended by all members of the emergency services in the area
Meanwhile, NHS South West London urged people to ensure they have sufficient food and medicine, keep bedroom windows closed, wear multiple layers of thinner clothing and 'heat rooms you spend most time in, to 18C if you can'.
Sir Sadiq Khan said homeless people in London will be sheltered with temperatures set to plummet below freezing during ice-cold evenings.
The Mayor's Severe Weather Emergency Protocol (SWEP) has been activated to provide emergency accommodation for rough sleepers.
It comes after a 67-year-old man who was pulled from the water during a major rescue operation off the East Yorkshire coast died.
Rescue crews launched a dramatic search following reports of a 'number of people in difficulty in the water', near Withernsea, East Riding of Yorkshire, on Friday afternoon as the Arctic chill grips Britain.
HM Coastguard, Yorkshire Ambulance Service, Humberside Police, and Humberside Fire and Rescue all scrambled crews to Withernsea at around 3.15pm to try and rescue those in the freezing sea.
Yorkshire Ambulance Service initially said four people had entered the water. But by 7.15pm on Friday, HM Coastguard said it was searching for two people, having previously said it was reporting to 'a number of people in difficulty in the water'.
Humberside Police has confirmed that the man was pulled from the water, but tragically died shortly after at the scene.
The rescue operation continued into the night amid freezing temperatures.
It comes just one day after people were not allowed to enter the sea for the annual New Year's Day swim event due to large breaking waves, and amid a yellow weather warning for snow and ice on the Yorkshire coast.
Snow showers are expected overnight, with the Met Office reporting a likelihood of around one to three cm of snow, with up to eight cm possible in places.