Hazardous weather conditions are threatening widespread disruption across Ireland as winter tightens its grip.
Snowfall of up to 10cm (four inches) has been forecast in some areas, with gale force winds, heavy rain, flooding, sleet and plunging temperatures predicted to upset travel plans.
Several flights in and out of Ireland have been cancelled, DART services in Dublin have been axed and bus services in some remote areas and higher ground have been diverted or delayed.
Met Eireann has issued a weather warning of further heavy falls of snow, mostly in Ulster, as well as sleet and snow showers over north Connacht and north Leinster. Sub-zero temperatures will lead to icy patches while high winds in coastal areas are expected to cause some flooding.
Road safety chiefs appealed to motorists to use extreme caution and make preparations ahead of journeys where local conditions are dangerous. Roads in parts of Wicklow and Meath were impassable, the AA cautioned.
Aer Lingus was forced to cancel at least 16 flights between Ireland and the UK, as heavy snowfall across the Irish Sea hit airports in London, Bristol, Cardiff and Bournemouth. Ryanair has also axed a number of services.
Irish Rail had to cut evening rush-hour DART journeys between Bray and Dun Laoghaire after the lines were flooded at Sandycove, in south Dublin. Bus transfers have been put in place.
Jane Cregan, Irish Rail spokeswoman, said teams were on stand-by in other parts of the country to clear railway tracks in the event of snowfall.
Some Bus Eireann services were delayed in Wicklow and Cavan while officials were continuing to monitor routes and local conditions. "We are coping quite well with the conditions for now," said company spokesman Andrew McLindon.
Dublin Bus said drivers were experiencing some difficulties on routes near the Dublin Mountains and north Wicklow. Diversions were put in place where there is flooding and icy roads.