Motorists have been warned to take extra care on the roads after snow fell across much of Wales overnight.
The M4 was closed eastbound for a number of hours at junction 48 near Llanelli after a six-vehicle crash.
The weather was causing disruption to travel in south east, west and north east Wales, as well as closing more than 120 schools in south east Wales.
Emergency services say that most main roads are passable but warned of hazards on minor roads.
Snow closed the museum to everyone, except those at a very white wedding
The crash on the M4 eastbound at Hendy at 0755 GMT led to a two-mile tailback, with traffic being diverted via a slip-road. One person with a neck injury was freed by a fire and rescue crew and two more people were slightly injured.
In Pembrokeshire, one man was taken to hospital after being trapped in his van after it overturned near Dredgeman Hill, Haverfordwest, at 07.50 GMT.
Three people were injured after a crash on Mountain Road, Pentyrch near Cardiff at 1100 GMT, with one person having to be cut free.
There were particular problems on roads in south-east Wales and the heads of the valleys, while the Wrexham and Flintshire areas were also affected.
A LOOK AHEAD
Derek Brockway, BBC Wales weather forecaster
We have seen the worst of the snow in Wales for the time being.
There will be a few wintry showers over the next couple of days but hit and miss.
It's going to stay cold and icy with the risk of freezing fog patches.
The latest thoughts for Christmas are that it will stay on the cold side, with some frost and rain, turning to snow showers on high ground.
The A465 is closed westbound at Rhymney Bridge due to an accident.
The A470 was closed in both directions due to ice and snow between A4059/A472 (Abercynon roundabout) and A4060 (Pentrebach roundabout) in Rhondda Cynon Taf but has reopened with one lane in both direction.
One lane was closed due to snow on the M4 in both directions between J32 A470/A4054 (Coryton Interchange) and J38 A48 (Margam off slip).
The A469 was closed in both directions at New Tredegar, Caerphilly county, due to an accident between A4049 (New Tredegar) and Chapel Road (Pontlottyn).
The A4076 Vine Road at Johnston, Pembrokeshire was also closed due to an overturned lorry near Kiln Road.
Power Station Hill at Tonteg near Pontypridd was also closed.
Much of south and west Wales has been covered in a blanket of snow
First Cymru said at 0930 GMT no bus services were running from Maesteg, while in Bridgend, there were no services to the valleys although an assessment is being made. A shuttle service is running between the bus station and Bryncethin and Brynmenyn.
In Neath, bus services to Cimla were subject to delay and in Port Talbot were running on main roads only, apart from the Baglan estate. Between Llanelli, Pontarddulais and Swansea, the company's services were only travelling on main roads, not estates.
Stagecoach said early morning services in Torfaen had been disrupted. The 21 and 22 have resumed services to Blackwood and Ebbw Vale but are still not able to serve Swffryd.
Torfaen council has cancelled refuse and recycling collections for Monday from Blaenavon to Pontnewydd, which will now be collected on 28 December, but they are expecting to resume collections on Tuesday.
Cardiff Bus said it was operating as normal with all areas being covered, although some services may be slightly late.
A little mud splattered but snow-free, Tony McCoy and Galaxy Rock after winning at Ffos Las Racecourse
Fire crews in the city were called to a report of a dog stuck in an icy lake near Pentwyn, but when they arrived the RSPCA were in attendance and could find no sign of the dog, with the owner no longer at the scene.
The National History Museum at St Fagans in Cardiff has closed to the public because of icy conditions but a wedding due to take place at the Oakdale Miners' Institute on the site is going ahead.
Air passengers from Wales travelling to Bristol International Airport were told four Easyjet morning flights to Glasgow, Palma, Belfast and Krakow were cancelled.
But Monday's National Hunt race meeting at Ffos Las near Llanelli went ahead as planned after the course passed a morning inspection.
Tuesday's meeting at Bangor-on-Dee has already been abandoned due to a frozen track after an 0800 GMT inspection.
Clerk of the course Ed Gretton said: "We are not raceable at present as parts of the course are frozen with frost embedded in the track and we don't think it will improve sufficiently enough in time.
"It got to minus three last night and the same is forecast again tonight and with the short days it will just not rise quickly enough."
Steve Thomas, of the Welsh Local Government Association, said local authorities should have enough salt for roads.
"The winter has been fairly quiet so far so people obviously learned lessons from last year and stocked up," he said.
"Councils are prepared for it but, at the same time, conditions are going to be difficult."
Have you been affected by snow? We asked you to send us your comments. Here are a selection:
Why do a small majority of people choose to drive like idiots when there is snow and ice under the tyres. Sensible gaps between vehicles are always a must, but some still insist on driving too close when the roads are dangerous. 4x4s are amoung the worst culprits - they might feel safer up high, but they will still inflict maximum damage is adequate care is not taken. Richard Morgan, Bridgend, Mid Glamorgan
The snowfall overnight in Newport was light enough that by early morning, it had all frozen into a layer of ice covering all road and pavement surfaces. Walking to work was something of an adventure! Michael Warren, Newport, Wales
A snowy scene in Monmouthshire on Monday morning
the bbc forecasted 'light sleet showers' yet seem to have about 3 inchs of snow outside. Richard, tonypandy. Rhondda
It's pathetic that there are no snow ploughs down the streets throught Rhymney, Pontlottyn, Fochriw and Abertyswwg which is ridiculous. The council needs to get their act together as nobody can get out and get on with their day. Carl, Rhymney
It's great fun! Although I tried to drive the car, soon I realised I would have to drive up a hill. I turned back around with great difficulty as I was wheel spinning on the icy roads, parked up walked to Cadoxton train station..on the way there where a few 'Whopop! slips!!! I then got to my destination-the train station and fell on the ice LOL I just chuckle to myself! I has to txt all my family and friends to warn them before vernturing out. You just have to be sensible and have a laugh with the great weather!rebecca neilson, Barry
Merthyr this morning was like a disaster area, the main roads had not been ploughed, if they had been gritted then it had no effect. The main A470 dual carriageway was closed at Pentrebach. A total shambles by the council again. Brent, Merthyr Tydfil Wales
I live near the top of a very large hill on the outskirts of Caerphilly. It was very nice to see some of my neighbours out this morning helping to shovel snow of the road, pushing stuck cars up the hill and laying down extra grit. It was certainly warming to see everyone banding together - which can only be a good thing seem as I currently have no gas (or heat!) and am freezing waiting for the engineer to come! Leanne, Caerphilly
It,s nice to see the snow. the children seem to be enjoying themselves. But DON,T forget the eldery. it,s worth two minutes of your time. Make sure they stay warm. Hope we all can enjoy the snow. paul lloyd, nelson
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