Road surface temperatures are due to drop as low as -2 C overnight and Devon County Council's gritters will be treating the county's main routes this afternoon and overnight. Scattered wintry showers are expected this evening and into tomorrow, and this may fall as snow on higher ground of Dartmoor and Exmoor. Gritters have already been treating routes on Dartmoor from around 11am this morning ahead of snow showers on parts of the moor earlier today. With the Met Office issuing a Yellow Warning for ice affecting the whole of Devon until 10am tomorrow morning, the county council is reminding people that conditions could be hazardous. Councillor Stuart Hughes, cabinet member for highway management, said: "Tonight may not be the coldest night of the winter but given the amount of wet weather we've had in the past couple of weeks, the sub-zero temperatures could well cause problems with icy patches, particularly on untreated surfaces. "Gritters will be carrying out multiple treatments in most parts of the county, but we can only treat around 2,000 miles of our network, so we would encourage everyone to be mindful of conditions. Reduce your speed and allow extra time for your journey."Devon County Council is issuing the following advice: - Avoid overnight travel unless absolutely essential as roads will always be more hazardous at night with less traffic and colder temperatures; - Never assume a road has been salted. Remember that showers or rain will wash salt off roads leaving them prone to ice, and in extreme cold even salting will not stop ice from forming; - Allow additional time for your journey and reduce your speed; - Drive with care and according to the conditions.For more information and travel advice from Devon County Council visit www.devon.gov.uk\/winter_travel .