Stranded vehicles including a lorry have caused heavy traffic and long delays on the A11.
The road was blocked in both directions between the B1135 at Wymondham and the A47 at Cringleford.
At 11.45am traffic on the southbound carriageway was released.
And just after 1.25pm the northbound carriageway was reopened between Thetford to Spooner Row.
There were delays around Wymondham due to broken down lorry but the road was flowing by 3pm.
Queues starting forming just after 7am this morning after vehicles were left following severe weather overnight.
Some people been stuck in the delays, which stretch as far as Thetford and Norwich, for nearly three hours.
Welfare checks were carried out by police officers and water was handed out to those who are stuck in traffic.
There were reports that people have decided to make a bad situation better by having snowball fights with other drivers.
A spokesman for Highways England said gritting had been taking place 'around the clock'.
They added: 'Overnight there has been gritting taking place throughout the region.'
Norfolk's police are telling drivers to only get behind the wheel if it is 'completely necessary'.
The reported number of road traffic collisions today has been 12 non-injury incidents and one injury.
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