Some motorists have abandoned their cars on icy roads
Heavy snow and freezing temperatures have brought widespread disruption across north west England.
A lorry driver was killed on the M60 at Stockport in one of a multitude of crashes reported to police around Greater Manchester.
Flights were suspended at Manchester, Liverpool and Blackpool airports and many public transport services were badly hit, particularly buses.
But thousands of children enjoyed a day off as hundreds of schools were shut.
Manchester Airport reopened on Tuesday afternoon after its runway was cleared, but Blackpool International remained closed until at least 1600 GMT.
Liverpool John Lennon Airport's runway was shut for the second time on Tuesday afternoon after more snowfall. A further decision was expected at 2000 GMT.
More than 60 flights in Manchester were cancelled and passengers have been urged to check with their airline.
The North West Ambulance Service (NWAS) said it had been inundated with calls and warned that paramedics would only be sent to emergency cases.
A spokesperson said: "This is due to the fact, particularly in Greater Manchester, we are unlikely to be able to reach patients with minor injuries or symptoms.
"We are having to stringently prioritise all of our 999 calls and despatch our resources to life-threatening cases only."
Other effects of the adverse weather have included:
- All proceedings at Manchester Crown Court cancelled for the day
- Cheshire Police issued a warning for parents after a bus driver was hit in the face by a snowball thrown by a child.
- Carling Cup clashes between Manchester City and Manchester United, as well as Blackburn and Aston Villa, cancelled
- Filming suspended on Coronation Street
- Examinations for Liverpool John Moores University students at Aintree Racecourse on Wednesday cancelled
- Bin collections suspended in Wirral and parts of Liverpool
- Trafford indoor winter sports centre, the Chill Factore, closed because of the snow
Police in Greater Manchester, Lancashire, Merseyside and Cheshire have urged motorists not to travel unless necessary, with some officers describing the conditions as "treacherous".
Manchester Airport was closed while staff cleared the runway
The M60 remained closed at junction 25 on Tuesday afternoon for investigations into the fatal collision between two lorries.
BBC weather presenter Dianne Oxberry said up to 20cm of snow had fallen overnight on higher ground, with a further 10cm expected later.
Temperatures are expected to drop to about -5C overnight, leading to icy conditions everywhere, she added.
All Arriva bus services on Merseyside were cancelled on Tuesday afternoon, while only skeleton services were operating in other areas.
In Manchester, Metrolink trams were not running on the Eccles line, while some delays to rail services were reported.
Regional transport operators urged passengers to check their websites for updates.
Greater Manchester Police (GMP) urged the public to only call 999 in an emergency - such as a threat to life or a crime in progress.
Supt Karan Lee said: "I would like to reassure the public that we will attend all emergencies however our response vehicles could also be hindered by the adverse weather conditions and it may take us a little longer to get you."
Police have been dealing with a "multitude" of minor collisions, as well as a number of serious crashes, she told BBC News.
Earlier, Lancashire Police said there had been a 12-mile tailback on the M6 between junctions 26 and 27 southbound, with only one lane open.
In Greater Manchester, one man told the BBC he had abandoned his car on the A626 in Marple, Stockport, because of the conditions.
"I gave it a go. I got out of my house about eight o'clock, started driving out of the estate and got as far as Dan Bank," he said.
"There are cars skidding here trying to get up so it's quite treacherous."
A number of lanes were also closed on parts of the M6 and M60 in Greater Manchester, and earlier the M58 was shut completely.
Some roads in higher remote areas of Oldham and Rochdale have been described as impassable.
The Highways Agency said continuous salt treatment was being undertaken on the motorway network in high risk areas.
Spokeswoman Jenny Hart said there were "very difficult" driving conditions on many roads and urged motorists to avoid travel wherever possible.