Heavy snow is expected to hit most of the UK next week as a cold blast of air known as "the Beast from the East" arrives from Russia.
Forecasters say the freezing weather could bring travel disruption and power cuts as Britain faces its coldest February week in five years.
Severe weather warnings are in place for England, Scotland and Northern Ireland, with snow showers forecast on Monday, Tuesday and Wednesday.
Temperatures are expected to drop to -5C overnight and remain cold throughout the week, with the icy conditions predicted to last until the middle of March.
The Met Office said: "There is the potential for travel delays on roads, stranding of some vehicles and passengers, as well as delays or cancellations to rail and air travel.
"Some rural communities could become cut off. Power cuts may also occur and other services, such as mobile phones, may be affected."
A yellow "be aware" warning for snow has been issued for eastern and central England on Monday, which is extended to cover Scotland, parts of Wales and northern and southern England on Tuesday.
The warning covers most of the UK on Wednesday, with heavy snow showers forecast across the country.
Forecaster Marco Petagna said five to 10cm of snow is expected in places on Monday and Tuesday, while 10 to 15cm is predicted on Wednesday afternoon.
The Met Office has also issued an amber cold weather alert for England – its second highest level – which warns of increased health risks to vulnerable and elderly people.
The AA urged drivers to take extra care and said it was mobilising extra resources for an increase in demand for help over the coming week.
The prolonged spell of cold weather has been blamed on a rare North Pole phenomenon called "sudden stratospheric warming".
The event disrupted the polar vortex in the upper atmosphere, resulting in bitterly cold air sweeping in from Siberia, according to forecasters.
Sky News weather presenter Joanna Robinson warned that while spring should be approaching, winter was "far from over" for the UK.
"There is increasing confidence that easterly winds will develop, dragging in very cold air from Siberia as early as next week," she said.
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"This set-up is often referred to as the 'Beast from the East'.
"It's not just the UK that will be affected – much of Europe will see temperatures well below average."