Gritters have been out in the city of Newport all day

The capital had escaped much of the snowfall which has caused chaos on the roads and forced the closure of dozens of schools.

But a flurry of snow mid afternoon has left fears that it will turn to ice as the evening temperatures drop, adding to the travel troubles for people making their way home from work.

The Met Office has issued a drifting and heavy snow across the area on Thursday evening, creating dangerous conditions for drivers across the region.

If you have to drive, drive according to the conditions, keep your speed down South Wales Police

The Rhigos and Bwlch mountain roads in Rhonda Cynon Taf are closed and the authority's gritters have spread some 300 tonnes of salt on remaining roads.

Driving in the Upper Afan Valley is possible only with extreme care.

Many bus services in the Cynon Valley have been brought to a standstill, and Shamrock Coaches has cancelled its services in Merthyr Tydfil.

Motorists on the Heads of the Valleys road have already found themselves gridlocked, with long delays and tailbacks as people leave for home early.

Gritters in the city of Newport have been out all day.

Schools closed

Thomas Motors, of Barry, which runs a number of bus services in the Vale of Glamorgan, has suspended its timetable.

The wider travel problems follow a bad start to the day in Cardiff when morning rush-hour commuters were delayed by a series of unrelated accidents.

South Wales Police Road Safety Officer, Sergeant Nigel Whitehouse, said the advice to motorists was to exercise extreme caution if they had to make a journey.

He said: "Unless you have to make a journey, please to not make it, and stay at home.

"If you have to drive, drive according to the conditions, keep your speed down.

"If you are going out, be prepared, take an extra blanket with you, and perhaps a torch."

But the bad weather has meant a day off school for thousands of pupils.

Rhondda Cynon Taf reported 46 schools had been forced to shut their doors. Torfaen saw three close and more were closed in Merthyr Tydfil.