Relentless storm fronts battering the country will see water levels reach their highest mark since the disastrous floods that washed out homes and businesses in 2009.
Storm Frank has seen water in the Shannon region continuously rise in recent days, and the tail end of the storm is likely to bring further damage when it hits today.
Thousands of homes were without power yesterday as winds of up to 110km battered Valentia in Co Kerry.
More than 2,000 homes in Westport had no electricity, and 3,000 in Donegal, Kerry, Cork, Tipperary and Sligo were also cut off.
Kerry Mountain Rescue personnel had to scale Carrauntoohil as the storm raged to go to the aid of a climber who had suffered a broken leg.
Last night business premises on the main street of Graiguenamanagh, Co Kilkenny, were inundated with flood waters.
Met Éireann forecaster Evelyn Cusack warned that more rain and high winds will hit the country today, with no sign of a let-up in the week ahead.
"Forecasting models are one week to 10 days ahead, and in that period the jet streams over Ireland will get more waves of wind and rain coming in," she said.
"There will be a sting in the tail, with a window of very strong winds and a spell of heavy rain."
This is expected to cross the country between 6am and 11am today and is being classified as a separate storm to Frank and is being called Storm Gertrude.
Status orange weather warnings were issued for the west coast and extended to southern coasts and counties Kilkenny, Carlow and Wexford.
OPW engineer Jim Casey said conditions in Athlone are also likely to deteriorate in the coming days.
"There is an ongoing risk to Athlone and with increased rainfall it will go above what it is currently at," he said.
"We still remain in a severe flood situation, especially in the Shannon catchment, and all ongoing flood defence efforts, such as pumping will have to continue for some time yet."
The latest warnings come after the ESB warned that further torrential rainfall of more than 40mm will see water discharges dramatically increased at the Parteen Weir upstream of Limerick city, with inevitable consequences for flooding in Limerick and Clare.
The discharge has also been increased from 180 to 200 cubic metres per second at the Inniscarra Dam in Co Cork. ESB engineering manager Tom Browne said further rain will bring more discharges and flooding in Cork city.
"I think an increase to 250 would definitely have water out on the Carrigrohane Straight, as that is a road that regularly floods," he said.
"It will also mean that there will be more water going over banks and there will be a risk to property on the western side of the city."
While the ESB yesterday increased discharges from 405 to 440 cubic metres of water per second at Parteen, it warned that further increases are inevitable and could pass levels seen in the disastrous floods of 2009.
"The Parteen discharge in 2009 went to 500 cubic metres per second and, depending on the weather that we get in the next couple of days, it could go to that level again," said Mr Browne.
Meanwhile, around 80 farmers in the worst-affected areas of the country are receiving emergency fodder for their livestock.
Agriculture Minister Simon Coveney said: "The assistance is modest but important for those hardest hit by these floods."
The Army said 49 soldiers have been deployed to help flooded communities. Thirty-one had been deployed in Athlone since Monday, filling sandbags and reinforcing embankments, and more soldiers are working in Gort, Co Galway.
In Clonlara, Co Clare, Defence Forces engineers are using flat-bottomed boats and pumps to channel water away from homes and farms.
Sandbags were also being handed out in Waterford at Dungarvan and Carrickphierish as the River Suir rose last night.
Two flights from Kerry Airport were cancelled because of stormy conditions. The promenade in Salthill, Galway, was closed to traffic as waves crashed onto the road while in Roscommon an empty car was blown into the Shannon.