The council said it had to use existing supplies in the best way
Gritting of low-priority routes in Cumbria has been halted because of supply problems caused by soaring national demand for rock salt.
The county council said the firm which supplies local authorities from its Cheshire salt mine is unable to deliver to Cumbria for the foreseeable future.
Priority one and two routes will be gritted, but the remainder - mainly minor roads in rural areas - will not.
Alternative supply options are being examined, said the council.
More than 4,200 tonnes of rock salt is currently stockpiled - more than in many other counties, according to the authority.
A full county-wide gritting run uses around 300 tonnes.
Third priority routes are gritted only during periods of prolonged icy conditions and when first and second priority roads are clear.
Councillor Tony Markley, cabinet member for highways, said: "Thankfully Cumbria is in a better position than many other councils and we have more supplies left than many other areas, but we do need to be careful about using what we have got in the best possible way.
"Unfortunately, for some people who live near minor roads this will mean that a road that they would normally expect to be gritted during a prolonged cold spell will not be gritted.
"I'd urge all drivers to be extremely careful and think hard about how essential a trip is before making it."