Police are dealing with multiple collisions on the A19 and a jackknifed lorry which has closed the road.
Durham Police say the southbound carriageway is closed at Sheraton due to the lorry blocking the road.
Conditions are being described as a 'complete whiteout', and officers are now advising against using the A19 at all.
The closure is likely to remain in place for a considerable time.
A number of collisions on the A19 between Dalton Park and Peterlee also resulted in slow moving traffic on both carriageways.
Elsewhere in the region, damage has been caused to the A66 snow gates, so although the road may at first appear to be open, it remains closed.
And both carriageways of the A1(M) are down to 40mph between J60 and J63.
A Durham Constabulary spokesman said: "We would like to reiterate that where speed restrictions have been put in place, they MUST be adhered to.
"A minority of road users are continuing to drive too fast despite the adverse conditions.
"Although road conditions are slightly better than yesterday, they are still treacherous.
"We continue to advise against all non-essential travel."