Wales snow: Hazardous road conditions as snow moves west
Heavy snow is moving into west and mid Wales, bringing a spate of road crashes in hazardous driving conditions.
Dyfed Powys Police said main roads in Carmarthenshire were passable but advised motorists only to make essential journeys.
Three people were taken to hospital after a minibus crash and more than 475 schools have closed.
Cardiff and the south east saw the heaviest snowfall overnight with 10cm (4in) in places.
Most early school closures were across the south Wales valleys, Cardiff and Swansea but schools across Carmarthenshire have been shutting as snow moved in with parents at more than 20 schools asked to collect their children.
Eight schools in Pembrokeshire also closed early but the council said major travel disruption is not expected and main routes were passable.
A school bus, carrying 40 pupils home from Ysgol y Preseli in Crymych, slid off a road at low speed near Maenclochog. There were no injuries and the pupils were able to stay on board until a relief bus arrived.
Head Michael Davies, a teacher at the school for 25 years, said the conditions were probably "the worst I have ever seen".
There is a Met Office yellow warning - meaning be prepared - for snow in Carmarthenshire, Bridgend, Swansea, Neath Port Talbot, Cardiff and Rhondda Cynon Taf.
A further 2-5cm (1-2in) of snow or sleet is likely in places, with perhaps as much as 10cm (4in) over high ground.
The poor weather have been a spate of road crashes across south and west Wales.
Two motorcyclists were taken to hospital after a crash involving two cars in Birchgrove, Swansea, at 09:15 GMT.
In Carmarthenshire, three people were injured in a minibus crash in Drefach, which has blocked the Meidrim to Bancyfelin road.
A motorist was treated at the scene after a crash with a bus in Trimsaran. There were also road crashes as the snow caused problems in Llanelli.
Carmarthenshire Council said the situation was "patchy and changing" but its priority was helping keep 1,000km of main roads open. It has already distributed 2,000 tonnes of salt in recent days with gritting teams working 12 hours shifts.
Councillor Colin Evans however said they had received reports of some motorists abandoning their vehicles.
"One of the issues is people panicking basically and abandoning their cars," he told BBC Wales.
"How bad that situation is at the moment I'm not sure but it doesn't help matters when we're trying to clear these primary routes."
In Pembrokeshire, vehicles were struggling up Rhos hill on the A478 between Blaenfos and Cardigan. The council said minor roads were passable with extreme caution.
In Torfaen, a lorry driver was taken to hospital after his vehicle overturned on the A4042 northbound at Pontypool.
Hazardous driving conditions were reported along the whole of the M4 in south and west Wales.
Problems are also reported across much of Rhondda Cynon Taf, the A465 Heads Of The Valleys road and Swansea.
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The Bwlch, Rhigos, and Maerdy mountain roads in Rhondda Cynon Taf are closed due to snowfall but the Caerphilly mountain road is passable with care.
Vale of Glamorgan Council said its main routes had been ploughed and gritted and were passable with care.
Rail problems unrelated to the snow are adding to the travel disruption.
Arriva Trains Wales said there were signalling problems at Abercynon bringing delays to services between Cardiff and Merthyr while trains to Cardiff Airport face disruption due to a problem at a level crossing at Rhoose, Vale of Glamorgan.
There was some disruption to First Cymru Buses services in Swansea.
Stagecoach said some of its bus services in Aberdare and Merthyr were restricted to main roads and were not calling at some estates.
Cardiff and Vale University Health Board says a number of out-patient clinics have been cancelled.
The meals on wheels service in the Rhondda Cynon Taf will run as normal on Wednesday with the help of hired-in 4x4 vehicles. Only a limited service was possible on Tuesday and it was cancelled in the Rhondda and Cynon valleys.
In Swansea, the Tycoch and Llwyn y Bryn campuses of Gorseinon College were closing early, except for students taking exams.
In Flintshire, the owner of an animal rescue centre has criticised "callous" owners who left an abandoned dog chained overnight in snow.
John Morris said the Jack Russell terrier - nicknamed Frosty - was found chained outside the North Clwyd Animal Centre, Trelogan, on Wednesday morning.
It had been tethered with a metal chain and "just dumped".
The Met Office said more sleet and snow are expected to spread into mid Wales and the north east.
The lowest temperatures forecast were around freezing or below -3C (26F) in places.
Parts of the west and northwest will stay dry.
The bout of snowy weather began last Friday when a rare red warning of snow preceded a day which saw more than 1,000 schools close, and there has been disruption to varying degrees across different parts of Wales each day since.
On Tuesday nearly 500 schools were closed and major roads disrupted.
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