Commuters face widespread travel disruption on Wednesday morning after parts of the UK saw heavy snowfall and ice.
The Met Office put in place a yellow warning for ice for much of southern England, the Midlands and eastern Wales from 5pm on Tuesday to 10am on Wednesday.
Several other warnings for snow and ice have been in force across the UK, with the Met Office advising that vehicles could be stranded, power cuts may occur and rural areas could be cut off.
The forecaster warned of snow showers developing during Tuesday evening and continuing overnight into Wednesday morning. The showers may be heavy at times and accompanied by lightning in some areas.
Some lying snow could reach up to 10cm or more over higher ground and ice is expected to form on untreated surfaces. Met Office spokesman Stephen Dixon previously told the PA news agency: "We've had a fairly mild November so far. So it'll feel like that first taste of winter for many with that snow and ice risk layered on top."
He added: "The highest accumulations are likely over the mountains in Scotland, where over higher ground you could see around 20cm of snow through this week accumulating on the ground.
"They are not necessarily the most disruptive snowfalls, but it only takes a couple of centimetres on lower ground to cause some level of travel disruption."
Tuesday saw widespread disruption across the UK, with more than 200 school closures reported by Tuesday afternoon. Snowfall was also widely reported, with 12cm of lying snow recorded at Watnall, Nottinghamshire, on Tuesday morning as an Arctic airmass influenced the UK's weather.
Thousands of train passengers suffered disruption on Tuesday morning and a Stagecoach bus in Aberdeenshire toppled onto its side with a passenger on board in icy conditions.
The UK Health Security Agency (UKHSA) has issued the first amber cold weather health alert of the season, warning conditions could be dangerous for vulnerable people, including the elderly.
The amber warning covers the east and north of England, the Midlands, and Yorkshire and the Humber, with yellow alerts coming into place for the South East, South West and London until 6pm on Saturday.
Met Office chief meteorologist Neil Armstrong said: "With cold Arctic air firmly in place over the UK, continued winter hazards are likely through much of this week, with further updates to warnings likely in the coming days."
The Met Office has issued a yellow warning for snow and ice along the east coast of Scotland and England from Berwickshire to Suffolk from 6pm on Tuesday to midday on Wednesday.
A yellow warning for snow and ice has also been issued for Northern Ireland from 6pm on Tuesday to 10am on Wednesday, with a separate warning also in place across most of Wales and parts of the West Midlands until 10am on Wednesday.
There are also snow and ice warnings in place covering the north of Scotland until 10am on Wednesday and parts of western Scotland from 7pm on Tuesday to 10am on Wednesday.
The Met Office said cold northerly winds will continue through the week across much of the UK, with further warnings likely. It added that temperatures were likely to increase from the south-west this weekend, though this will be accompanied by some strong winds and heavy rain.
The Alzheimer's Society warned that cold weather can be "particularly challenging" for people with dementia.
"Colder temperatures can be difficult for a person with dementia to adjust to, and they may not always be able to communicate that they are cold - or they may not even recognise it themselves," the charity said.
Another charity, Asthma + Lung UK, urged those with lung conditions to be "extra careful". The charity warned cold weather can trigger potentially life-threatening asthma attacks or "flare-ups" for people with other lung conditions.
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