Motorists have been urged to take extreme care on the roads as further snow fell across much of the country today.
In Dublin tonight, road conditions are very wet around the city and slushy in the suburbs, with motorists urged to drive with caution due to intermittent snow showers.
Dublin Bus services have been badly hit. There are no services to Lucan village, while buses to Enniskerry are terminating at Kilternan.
Snow has resulted in dangerous driving conditions in many parts of Kildare, Monaghan and Wicklow.
AA roadwatch reported ice along the N7 route from Naas in Kildare through to Citywest.
In Wicklow, snow and slushy conditions are causing problems in Enniskerry and Glencree, where it is snowing heavily. Gardaí are advising motorists to avoid the Wicklow and Sally Gap as both are impassable.
In Kilkenny, there was snow around the city and gardaí reported very dangerous conditions on back roads.
Aer Lingus was forced to cancel all its flights to and from London Heathrow yesterday, while some Gatwick routes and Ryanair flights between Shannon and Stansted were affected. Many flights are expected to experience knock-on delays today.
Met Éireann issued a severe weather warning for overnight and today. It said it will be very cold and icy this evening and overnight with further spells of sleet and snow and some heavy falls across the south and east leading. Temperatures will fall to below zero and as low as -3 or possibly -4 degrees in some places.
Tomorrow will also be very cold, with sleet and snow showers in many areas at first. These will become more scattered during the day with some drier brighter periods developing. However a band of sleet and snow will push into northern areas in the evening.
The snow and sub-zero temperatures drew an appeal from Age Action for people to keep in contact with their older neighbours during the week.
Iarnród Éireann advised customers that Dart services to Greystones, and Gorey commuter and Rosslare Intercity services, face disruption due to the closure of the rail line between Bray and Greystones. The closure is due to a rock-fall near the first tunnel on Bray Shuttle bus services are in place.
Barry Kenny of Iarnród Éireann said the closure could last for a significant period of time as there is still instability on the cliff face. “This is not a ‘back this evening’ job, it will certainly be all of this week and the potential is for it to go on a bit longer,” he said.
Fine Gael said yesterday's "commuter hell" as a result of the poor weather showed the urgent need for an emergency traffic plan for Dublin.
It said the Dublin Transport Authority must be "fast-tracked" and immediately begin work on an emergency plan for the greater Dublin area. A helpline must also be set up to provide accurate and up-to-date information, he said.
"Last night’s traffic chaos when thousands of commuters were stranded for at least four hours shows the urgent need for a Dublin rapid-reaction traffic plan," Senator Paschal Donohoe, the party's transport spokesman in the Seanad.
“This was probably the worst recent congestion seen in the greater Dublin area. Thousands of motorists were stranded both inside and outside the city. The fact that it was caused by a light dusting of snow shows just how ill-prepared the city is for adverse weather conditions. In spite of repeated weather warnings, the city authorities were clearly unable to cope."
The Irish Small & Medium Enterprises Association (Isme), criticised the local authorities, particularly in Dublin and surrounding areas, for what it said were "chaotic scenes that led to times of up to six hours for journeys of 15 miles or less" yesterday evening.
"Consequently, both individuals and businesses experienced inordinate delays that have resulted in increased absences, late attendance at work and late delivery of goods."
Isme chief executive Mark Fielding said: “It is completely unacceptable in this day and age, that both employees and businesses are forced to wait up to six hours in traffic to travel relatively short distances, particularly as the weather conditions were well flagged. It was obvious to everybody and in particular those stuck on the N7 or N4, that the roads had not been adequately gritted and that there was a complete lack of any traffic management plan."