Thousands of rail passengers travelling between London and Wales have been affected by flooding.
A lorry attempts to reverse out of flood water. Pic Gary Walker
First Great Western said there were service delays, alterations and cancellations on services.
Many roads, including the M4 and M5 interchange, were affected by snowfall and flooding, with fears homes and businesses could soon be affected.
Earlier flood watches have been upgraded to the more serious flood warnings by the Environment Agency.
This means they now expect flooding of homes and businesses, not just low-lying land.
Among the worst hit areas were Bristol, Gloucestershire, Wiltshire and Somerset.
Bristol Airport temporarily closed its runway and advised of delays.
West Country train operator First Great Western (FGW) said tickets for Friday would be valid for Saturday and Sunday and advised people not to travel unless necessary.
FGW confirmed flooding around Wootton Bassett in Wiltshire, Flax Bourton in North Somerset, and in three places between Swindon and Bristol Parkway, as well as in Gloucester.
It was advising customers to check with National Rail enquiries before travelling.
Network Rail said trains between Swindon and Bristol Parkway were being diverted via Bath Spa.
No trains are running between Bristol Temple Meads, Weston-super-Mare and Taunton.
The A370 at Backwell was badly flooded. Pic Ollie Coghill
The village of Broughton Gifford in Wiltshire remains virtually cut-off by flood water and roads around South Marston which were severely flooded earlier on Friday are now passable.
James Gray, the MP for North Wiltshire, who lives in Broughton Gifford, is one of those marooned.
Wiltshire Fire and Rescue Service said it had been a busy afternoon with more than 30 incidents as a result of the weather.
Snow is now falling in parts of Wiltshire and abandoned cars on the A419 are making driving difficult.
In Gloucestershire there is a flood warning in force for the entire length of the River Severn and a severe flood warning on the River Lid in Lydney.
The A417 is reported to be gridlocked with many motorists abandoning their vehicles.
Birdlip Hill remains impassable.
Gloucestershire Highways has 38 gritters on standby but is unable do anything till the rain lightens amid fears the torrential rain will wash the grit away.
There are concerns the freeze expected overnight will cause problems and also that the gritters may not be able to treat all areas in time.
Children had to be rescued from a primary school in North Somerset
Police are appealing to motorists in the county not to travel unless necessary and to keep their speed down.
About 10 homes in Lydney are reported to have been flooded.
Many motorists have told BBC Radio Gloucestershire of how they spent three to four hours on their homeward journey.
About 40 children had to be rescued from a primary school in North Somerset after a flooded road cut off access.
Some of the children were rescued from Chew Stoke Primary School using a tractor.
Head teacher Sarah Fuller said: "The children were excited and we played the incident down. The team of staff was absolutely fantastic. They got on the phones and told parents to come and collect their children.
"One couple trying to collect their children had their car swept away - it's been written off and it's now in farmland."
Avon Fire and Rescue Service said its high volume pump was used at Backwell to clear water from the A370. This was last used at Gloucester during the summer at the Walham electricity station.
Tim Aston, 40, and his wife and children have been living in a caravan on the driveway of their home in Tewkesbury since being flooded out in July.
Flooding at Wootton Bassett was blamed for the delays
"The kids have been sent home early from school because the river's coming up again," he said.
"It's really falling down here - I've got deja vu. We're feeling frazzled, we've really been through a lot and now we're twitchy."
At Chilcompton, two ladies had to be rescued after a car became trapped in water. And one person was rescued close to the Long Ashton bypass near Bristol, in similar circumstances.
Highways experts warned that the snow and rain could turn to ice overnight and warned drivers to be careful.
BBC meteorologist Richard Angwin said: "Between 25 and 35 millimetres of rain, sleet and snow fell across the region. That is about one third of the average January rainfall.
"Icy stretches are expected on untreated roads and drivers are advised to take great care on the roads.
"Further heavy rain is expected later on Sunday and there may be further localised flooding problems."
Have you been affected by this story? Send us your comments, using the form below.
The BBC may edit your comments and not all emails will be published. Your comments may be published on any BBC media worldwide.