Britain's transport network ground to a halt as the country's major airports closed their runways on what is traditionally the busiest weekend before Christmas.
Millions of people hoping to make an early getaway also faced travel misery on the nation's roads and railways as the big chill returned with a vengeance.
Meanwhile, all planes were grounded at London's Heathrow and Gatwick airports.
This weekend is expected to be the busiest for retailers and commuters in the run-up to December 25 but many were faced with widespread chaos as the latest cold snap took hold.
The AA had attended around 4,000 breakdowns across the UK, with calls peaking at 1,200 every hour - around twice the normal rate. By the end of the day, it expects to attend around 18,000 call-outs, compared to around 9,000 on an average Saturday.
Severe weather warnings of heavy snow and widespread icy roads are in place in London and the South East, the South West, the Midlands, the North West and Yorkshire and Humber. Wales, northern Scotland and Northern Ireland - which had experienced its heaviest snow for 25 years - were also issued with severe warnings.
Staff at Gatwick, Heathrow and Birmingham airports were battling to clear heavy snow as the latest blast of wintry weather showed little sign of easing. A BAA spokesman said: "Heathrow's runways are currently closed to allow snow clearing and to keep the airport safe. We're working hard with airlines to open the runways and to keep passengers moving, but it's important that people check with airlines before travelling to the airport."
Air passengers have already faced disruption at Exeter, London City, Aberdeen and Cardiff airports, while Belfast City reopened after it was closed on Friday night and Southampton Airport was set to reopen. Officials advised all passengers to check their flight status before travel.
As the RAC warned drivers not to make journeys unless absolutely necessary, there was also widespread chaos on major roads and motorways. Hundreds of motorists were left stranded on the M6 in Greater Manchester as the north west of England was hit with reported deluges of up to 25cm of snow.
Parts of the south were also blanketed and as much as a foot of the white stuff is expected to fall on parts of the South East and the Midlands. Forecasters expect the mercury will struggle to break above freezing in the next 24 hours. Lindsay Dovey, a forecaster with MeteoGroup, the weather division of the Press Association, said temperatures dropped to minus 15.5C in Aviemore, Scotland - with a possible low of minus 20C to come north of the border