Snow and ice blanketing the UK could last into the weekend and beyond as forecasters extend weather warnings.
The most severe conditions will be seen in Scotland, where amber snow warnings came into effect from midday Friday. Yellow snow and ice warnings are in place elsewhere until Monday.
Up to 40cm (15in) of snow could hit parts of Scotland on Friday, while the Met Office predicts as much as 5cm (2in) in areas across England and Wales.
Delays and cancellations to rail and air travel, disruption on the roads and power cuts are all expected as a result of the wintry conditions, the weather service added.
Yellow warnings for snow and ice came into force for large parts of England, Northern Ireland, Wales and Scotland at midnight on Thursday.
Different parts of the UK will be impacted at various times across the weekend, with a full list of affected areas available from the forecaster.
Most of the warnings were initially set to end on Saturday but the Met Office has issued a fresh wave of alerts, with the last ending on Monday.
The amber warnings in Scotland are currently due to be in effect until midday on Saturday.
Areas which will likely be affected by “blizzard conditions” include, Angus, Perth and Kinross, Grampian, Aberdeenshire, Moray and parts of the Highlands. These areas could see power cuts and vehicles risk being stranded, the Met Office warned.
With names like Sir Andy Flurry, Robert Brrrns, and Plougher O’Scotland, the Scottish gritter and snowplough fleet is out in force across the nation’s road network.
Meanwhile, multiple crashes were reported in Derbyshire, Lincolnshire and Nottinghamshire, National Highways said, as motorists are urged to seek alternative routes were possible.
People are being urged to plan routes carefully and to pack essentials in your car in the event of delays. Key items to bring include warm clothing, water, a blanket and ice-scraper.
Cold Arctic air is blowing across the UK, forcing temperatures well below average and increasing the risk of ice and snow showers.
Met Office forecaster Neil Armstrong predicts the cold spell “could last well into next week ” and “wintry hazards will continue with more weather warnings likely”.
With lower temperatures, amber cold health alerts from the UK’s Health Security Agency (UKHSA) cover the whole of England.
The alerts warn of a rise in deaths particularly among elderly and vulnerable people.
Other consequences of cold weather include temperatures inside hospitals and care homes dropping below the levels recommended for assessing health risks, and challenges for people keeping indoor temperatures at the recommended 18C, according to the UKHSA.
Stay up to date with the latest forecast on the BBC Weather website or app as details are likely to change.