Motorists are being warned to take care on the roads today due to flooding in many parts of the country.
In Co Kildare, at least eight crashes were reported on the M7 this morning due to extremely icy conditions between junction 16 Portlaoise and junction 14 Monasterevin.
A jack-knifed lorry on the N9 Kilcullen to Castledermot Road at Crookstown has been cleared, while an overturned car was partially blocking the Kilcullen Road.
The Kill, Naas and Sallins roads out of Johnstown are impassable due to flooding and in Celbridge village, the Old Town Road is flooded and the Barberstown and Ardarass roads are impassable. The Suncroft and Kildangan areas are also badly flooded.
In Naas, Garda Superintendent Patrick Mangan said there were a number of minor collisions this morning, mainly due to freezing road conditions following yesterday's rain.
Motorists had been taken by surprise by the conditions and some collisions were in part due to people not adjusting their driving behaviour to take account of them.
There is bad flooding in the Waterways area near Sallins railway station and a number of apartments have been evacuated.
A spokesman for Kildare County Council said some of the worst flooding in the county had abated, which was a "merciful relief". But issues persisted at the Waterways and around Straffan. The River Morrel, a tributary of the Liffey, was having problems draining down and this was contributing to the problem, the spokesman said.
He said the forecasting system used to predict ice on the roads had not indicated yesterday that there was likely to be a problem this morning.
But gritters were brought out as soon as it became evident that the road conditions were difficult.
Communities along the River Liffey were bracing themselves for further flooding as water levels rise upstream.
ESB said the flood on the Liffey has peaked and is abating slowly. But it warned it must now release water from a dam further upstream at Poulaphouca, Co Wicklow, where levels remain high.
“It is necessary to discharge water in a controlled and gradual way throughout today,” said a spokesman.
“This level of discharge should minimise the impact of flooding downstream in areas already affected by tributaries and other flood sources in the Liffey catchment.”
Kildare and Dublin county councils and the emergency services are monitoring the situation.
A nursing home and housing estate in Co Kildare were evacuated, with sandbags delivered to towns along the river by the army, local authorities, Civil Defence and fire service.
AA Roadwatch said roads across Kildare and at Strawberry Beds in Lucan where the Liffey burst its banks are flooded, as well as routes in counties Longford, Wicklow, Westmeath, Galway and Clare.
In Cork, there was a seven-car collision on the N8 south of the toll plaza at Watergrasshill due to severely icy conditions. There were up to six crashes on the N20 between Buttevant and Charleville due to treacherous driving conditions.
In Dublin, a truck jack-knifed on the Malahide Road near Campions pub. Gardaí were diverting motorists via Baskin Lane and Balgriffin Road.
Gardaí also dealt with a multi-vehicle collision at Lamb's Cross on the Enniskerry to Sandyford road, while the Clonee road out of Lucan between Laraghcon and Westmanstown was closed due to a crash and treacherous conditions.
In Tipperary, there were numerous crashes on roads in Thurles due to ice, including on the Holycross Road, Templemore Road and Nenagh Road.
In Co Kerry, the Tarbert to Ballylongford Rd (R551) is closed due to a serious crash and diversions are in place until the afternoon.
In Co Clare, a flood warning remains in place along the lower River Shannon. Areas concerned include Clonlara, Westbury and Shannon Banks.
In Co Limerick, the only passable route into Castleconnell is via Daly's Cross on the N7 Dublin to Limerick road.
Motorists are advised to avoid Leitrim village, while a stop-go system remains in place on the N4 Dublin to Sligo road at Carrick-on-Shannon.
A small craft warning has been issued on all coastal waters as winds reached force six today.
Additional reporting: PA