In Sussex, there were more than 40 crashes on the county's roads between midnight and 7.45am today, Sussex Police has said.
More than 30 of the accidents involved single vehicles sliding off the road because of black ice, prompting advice for motorists to drive with extra care.
Most of the collisions happened in rural areas and no serious injuries were reported, police said.
The Environment Agency has issued flood warnings and flood alerts across the UK.
Milder temperatures overnight will cause snow to thaw rapidly, with heavy rain expected to bring the risk of flooding in England and Wales.
Granada's Programme Editor Andrew Rigby was caught in the M6 snow chaos. Here he describes his nightmare journey home.