Snow is blanketing parts of the UK with up to 10cm (4in) expected in places, as the Met Office extended weather warnings for another two days.
Yellow snow and ice warnings were issued this morning for much of Britain between 5pm Tuesday and midday on Wednesday.
The Met Office issued a further warning this afternoon to be in place between 3pm Thursday and midday Friday.
Motorists have been told to expect delays on roads, and rail and air travel may also be affected.
The Local Government Association has said councils across the country are prepared with 1.4 million tons of salt, hi-tech gritters, and street cleaning teams ready to keep roads safe.
The Met Office warnings state there is a slight chance some rural communities could be cut off.
Cumbria Roads Police has told people to “please slow down” as it shared an image of a car overturned between junctions 36 and 39 of the A6 near the village of Shap.
A police car was seen stopped near a three-wheeled Robin Reliant on the A6, and highway patrol staff appeared to be seen helping a lorry that was struggling in the snow.
Snow has also covered swathes of North Yorkshire.
A motorist who was driving a snow-covered car with a just a small square of windscreen cleared was stopped by police in Caithness in the Highlands.
The driver was issued a fixed penalty notice.
Police Scotland warned other motorists to clear snow and ice from their vehicles before setting off.
The white stuff has been seen on train tracks in Orton in Cumbria with travel disruption expected across the country in falling temperatures.
Traffic Scotland tweeted snow was falling on parts of the M80 and M77 on Tuesday morning, while it also fell on the M8, M9 and A7.
In the Highlands, 10 schools were closed on Tuesday due to bad weather.
Staff at the Grains Bar Hotel in Oldham tweeted that flakes were “coming down thick and fast” in Greater Manchester.
Twitter user Jordan Cosby captured images of the freezing conditions in County Durham, and wrote: “The snow hasn’t stopped since first light this morning… but a few inches of snow wasn’t going to stop these locals from getting out!”
North Wales Police Roads Policing Unit tweeted that the A470 in Blaenau Ffestiniog is being cleared with a snowplough.
They added that officers saw two drivers on the wrong side of the road in the difficult conditions.
The A44 stretching from Aberystwyth to Llangurig in North Wales was also blanketed in snow.
The A470 Crimea #BlaenauFfestiniog now! Road is open and local authority colleagues are using the snow plough. However, drivers, please stay on your side of the road! We’ve just been faced with 2 cars on the wrong side, drivers said it looked clearer 🙈 Advice given 🙄 #staysafe pic.twitter.com/5dcCeFp0oy
— NWPRoadsPolicingUnit (@NWPRPU) January 29, 2019
Met Office meteorologist Marco Petagna has said around 1cm to 3cm (0.4in to 1.2in) could accumulate on low-lying levels.
He added there is the possibility of 5cm to 10cm (2in to 4in) of snow falling on higher ground.
Four separate yellow weather warnings have been issued which cover most of the UK.
Mr Petagna said London could experience some snow showers but they are unlikely to settle.
Sky News weather presenter Isobel Lang said: “Today there will be snow showers across northwestern parts of Scotland and Ireland.
“However for England and Wales we are looking at a band of more persistent rain and snow spreading eastwards reaching the South East during this evening.
“Snow is likely to develop over the hills of Wales, northern England and the Midlands with 5cm to 10cm possible.”
Temperatures fell as low as -7C (-19F) in the Highlands overnight on Monday, while the capital was at just about freezing as large parts of the country woke up to frost.
A band of rain will push from west to east on Tuesday morning, which could fall as rain, sleet or snow, particularly at peaks in Wales and northern England and Scotland.
Wintry weather will move across the Midlands and into the South East as the day progresses.
Snow showers could return on Wednesday and there is a risk of further disruptive snow and ice to parts of the country towards the end of the week.
The weather warning for Northern Ireland, running from 5.30am until 10.30am on Tuesday, said ice may form causing potential problems on untreated roads.
The remaining three are for snow and ice covering the western side of Scotland and into northwest England until 12pm.
They cover central regions, Wales and the North East between 12pm and 11am on Wednesday, and the South East, East Anglia and London from 9pm on Tuesday until 12pm on Wednesday.