Heavy snowfall overnight has caused major travel disruption and led to hundreds of schools being closed.
Amber and yellow snow and ice warnings are in place across the North East, the Midlands, the East of England and the South East, the Met Office said, with delays, closures and stranded vehicles expected.
Rural communities could be cut off completely, with power cuts and disruption to mobile phone signals possible throughout Tuesday, it added.
Here are the latest reported issues.
Hundreds of schools across the UK have been closed.
Three people were killed in a crash in Lincolnshire on Tuesday morning.
The A15 was closed in both directions at Baston after the fatal collision involving a car and a lorry on the A15 in Lincolnshire at 6.15am on Tuesday.
There were 20 collisions within three hours on Lincolnshire’s roads, including a school bus with 45 pupils on board, police said.
The children were unharmed after their bus collided with a car and veered off the road near Deeping St James.
A man died and another person suffered life-threatening injuries after three crashes on the A47 in Cambridgeshire.
All the collisions are believed to have involved the same vehicle and saw the road near Peterborough shut in both directions, police said.
Another person was injured and the A120 was partially closed after a 17-car pile-up between Colchester and Elmstead Market, Essex Police said.
Slow-moving traffic caused delays on the M2 in Kent westbound, between junctions seven and five, Highways England said.
HGVs struggling in the snow have caused delays on the M20 in both directions between junctions eight and nine, adding up to two hours to journey times, it added.
The A249 in Kent was closed following a crash between two lorries.
Meanwhile, dozens of stranded motorists had to be pulled from snow drifts on Tuesday morning, the AA added.
Vince Crane, of the AA, said: “With the sub-zero temperatures this week, drivers should allow extra time to properly de-ice the car and check their route before setting off – try to favour gritted roads if possible.
“Accidents happen when people rush so when on the road, leave plenty of space behind the car in front and drive to the conditions.”
Several train companies have been hit by cancellations and disruptions and services are expected to be extremely busy.
National Rail Enquiries said severe weather was affecting services on c2c, Greater Anglia, London Overground, South Western Railway, Southeastern, Stansted Express and TfL Rail.
Disruption may continue through Tuesday, Wednesday and Thursday, Network Rail said.
London Overground is running a stripped-back service, with between two and four trains per hour on many routes, and no services on other lines, such as between Romford and Upminster.
Train firm c2c is operating a limited timetable and advises its customers not to travel where possible.
Greater Anglia is also running a limited service, with less frequent and slower services between Norwich and Ipswich and cities such as London and Cambridge.
Trains between Norwich and Lowestoft, Felixstowe and Great Yarmouth are cancelled, among others.
Southeastern said it expects to run a normal timetable but if conditions worsen an emergency timetable may be introduced.
British Airways cancelled dozens of flights from Heathrow Airport on Tuesday, while easyJet said it is expecting some disruption.
British Airways said in a statement it was preparing for adverse weather until March 2, saying it was “likely to affect some of our short-haul and domestic flights”.
It added: “It is likely at times we will have to proactively cancel some services and re-book customers on to alternative flights.
“Customers on cancelled services can also claim a full refund if they no longer wish to travel.
“We are sorry for the potential disruption to your travel plans and are doing all we can to minimise the effect the poor weather may have on our flights.”
North east England and Scotland are expected to see the heaviest snow from Wednesday morning, with 15-25cm likely across Scotland, the Met Office said.