Heavy snow falling overnight has caused severe disruption in some parts of Cornwall.
The two main trunk roads between Cornwall and Devon - the A38 and the A30 - have been described as "atrocious" and "dangerous".
Newquay Airport is open, but travellers have been advised there could be some disruption to flights.
Snow has also affected Callington, Bude and Penwithick, with police advising drivers not to start their journeys.
First Buses said that some routes were not operating or were on a reduced service and not able to make all of their stops, including: the 41, 42, 82/82A, 83 and 84.
The rest were operating but could be subject to disruption because of ice, the company said.
Outbreaks of snow have turned to sleet or rain in some areas, increasing the risk of ice on freezing roads, the Met Office said.
Temperatures were also expected to drop to -3C overnight, it added.