Emergency services in Lincolnshire have called for military backup after the county was carpeted by snow.
The Army and RAF have been enlisted to help reach vulnerable people stranded by heavy snowfall.
We need to get doctors, nurses and others out to them so they can hopefully help us on that over the next 24 hours.Deputy Chief Constable Craig Naylor, Lincolnshire Police
Lincolnshire Police declared a “critical incident” amid major travel disruption.
Many roads in the county are closed and people have been urged not to travel unless “absolutely necessary”.
Deputy Chief Constable Craig Naylor said the military would be used to reach “people in the community who have life-threatening or life-changing conditions”.
“We need to get doctors, nurses and others out to them so they can hopefully help us on that over the next 24 hours,” he said.
More than 65 crashes have been reported and motorists have been stuck for several hours on the A46 after a number of HGVs jack-knifed.
Roads near Stamford are said to be “gridlocked” and conditions around Skegness are “treacherous”.
Among the major routes closed as a result of the snow are the A46 between the A57 and A15, the A153 between Horncastle and Louth and the A16 at Driby Top.
The A1 was closed in both directions for several hours earlier but has now reopened as has the A15 south of Bourne.
Supt Phil Vickers told BBC Radio Lincolnshire: “We have identified it as a critical incident, that’s meant that partners around Lincolnshire are co-ordinating the way we respond to calls that are coming in and there has been a significant volume.”
He urged drivers to stay with their vehicles until snowploughs and gritting teams are able to clear the area.
He added: “We are happy that we can sustain our response for a number of days without too great a difficulty, but we are keeping a close eye on the weather.”
The Met Office has issued an Amber warning for snow across the county, saying that “frequent heavy snow showers will continue for much of today”.
More than 200 schools have been closed across the county and Hunts Coaches said none of its school bus services in Lincolnshire were running.
Stagecoach Lincoln suspended rural services and no bus services are running in the Stamford area.
United Lincolnshire Hospitals NHS Trust said it was cancelling all “non-urgent outpatient clinics and operations today”.
All outpatient appointments have been cancelled at Grimsby, Scunthorpe and Goole Hospitals because of the poor conditions.