Thousands of home and business owners along the Shannon are bracing themselves for the river to peak in what experts are warning could be the worst floods in two decades.
From Athlone and the surrounding areas to Limerick city, the entire catchment is on high alert with waters expected to rise half a metre in total at some point in the next 24 to 48 hours.
The Army have been supporting efforts to contain the floods in many areas with sandbags on the streets of towns and villages like Ballinasloe, Athleague, Corofin, Craughwell and many parts of Clare.
Fresh drinking water distribution points have also been set up in many areas including by the Red Cross in Athlone, Portumna and Montpelier.
And compounding the fears of local people and emergency services, more rain is forecast.
Up to 35mm – nearly a third of what is normally recorded in December – is expected to fall on parts of Connacht, Donegal, Clare and Kerry over the course of the day, deepening the crisis for hundreds of homes.
Councils in Clare, Limerick and Ballinasloe called in the Army to help with flood defences.
In neighbouring Limerick seven pumps were in operation shifting water away from the villages of Castleconnell and Montpelier while an inflatable flood boom, which acts like movable defence wall, was being used in Castleconnell to channel the floods.
The ESB also took steps to reduce pressure on the swollen Shannon system by increasing the rate of flow at the Parteen weir to 375,000 litres a second, up from the normal 40,000 litres a second at this time of year.
It also increased flows through Inniscarra dam on the Lee in Cork.
Pictures from the Irish Air Corps taken over the Shannon catchment area showed the extent of the steady build up of flood waters in the wake of Storm Desmond.
Thousands of acres of farmland are under water with the Government putting a 5 million euro emergency response fund available to those worst affected.
Iarnrod Eireann said the Sligo line from Carrick-on-Shannon to Longford would remain closed until the weekend at the earliest due to flooding with the water about a foot over the track.
In Co Galway dozens of stretches of road have been closed.
The ESB warned the amount of water it was releasing over Parteen would likely cause f looding on roads, land and property close to the banks of the Shannon in Springfield, Montpelier, Castleconnell, Mountshannon, Lisnagry, Annacotty and the University of Limerick.
Limerick City and County Council warned it expects the waters to keep rising over the next few days.
“Council staff, assisted by members of the Defence Forces, are continuing to implement flood defence measures along the river bank and coordinate with local property owners,” it said.
The council also advised the public, particularly children, to avoid all flooded areas and to abide by the instructions provided by the emergency services and council staff.
The Defence Forces said troops had been deployed to support flood response work in four counties and remained on stand-by to help in other areas.
“Defence Forces mobility, manpower and specialist engineer assets remain available to assist our communities if required by local authorities,” a spokesman said.
In C lonlara, Co Clare, 15 troop s were supporting local efforts, while 30 had been dispatched to Castleconnell, another 12 in B allinasloe, Co Galway, and 35 in Athlone, with others put on notice in Donegal, Galway, Limerick and Cork.