Update 10pm: Tens of thousands of homes and businesses have been hit with a blackout as Storm Eleanor swept across the country.
ESB Networks said at least 55,000 households and other properties had been affected by the widespread outages in the west and north-west.
The areas worst hit are understood to be across Galway, Mayo, Sligo and Leitrim as the Atlantic storm moved in with gales gusting to 155kmh at Knock Airport.
Update on storm Eleanor:
Highest gust recorded at Knock Airport at 84 kts at 7pm this evening.— Met Éireann (@MetEireann) January 2, 2018
Two orange status - the second highest - weather warnings were put in place with the main threat coming from the wind and tidal flooding.
In Galway, streets around the docks were flooded after high tides breached defences and inundated the areas around the Spanish Arch, Claddagh, Dominick Street, Quay Street and nearby streets.
Water was more than one foot deep in places.
The Coast Road from the city to Oranmore was also impassable at rush hour as high tide combined with the strong winds to cause local flooding.
A number of drivers had to abandon cars near the town's shopping centre after floods rapidly hit while other cars in the railway station were badly damaged after seas were pushed over coastal walls.
Sea defences were also breached in the Salthill area with a number of cars also reportedly damaged.
There were also reports of spot flooding on the N85 Ennis to Ennistymon road in Co Clare.
The Road Safety Authority and other local authorities in Clare, Limerick and Cork had urged motorists and others to take additional precautions with the winter storm approaching.
In Gort, Co Galway households were warned about potential disruption to water supplies after power cuts hit the local pumping station.
Irish Water said ESB crews were on site but it would take several hours to get supplies back up again.
"We ask customers in the Gort area who have a mains water supply to conserve their water until the electricity supply is restored and the pumping station is back in full production," said a spokeswoman.
ESB Networks said outages were reported as far east as Cavan and Monaghan.
It said its crews were working to get people reconnected "where it is safe to do so".
"Aiming to restore as many customers as possible tonight, they will deploy again before first light tomorrow," a spokesman said.
"Further damage to the electricity network can be expected in north Leinster as the storm tracks east. Fallen trees on overhead lines are responsible for most of the damage to the network."
Update 8.28pm: Storm Eleanor: 55,000 ESB customers without power amid flooding and high winds
Gusts reaching almost 155km/h have hit Ireland's western shores bringing flooding and power outages.
ESB has said 55,000 of its customers across Ireland are without power.
The worst affected areas are Mayo, Leitrim, Sligo, Galway, Cavan and Monaghan.
Its repair teams are responding where safe to do so.
It aims to restore power to as many customers as possible tonight, while also deploying before first light tomorrow.
It is warning of further damage in Leinster as Storm Eleanor tracks east.
"If you come across fallen wires or damaged electricity network, never, ever touch or approach these as they are LIVE and extremely dangerous. Please report any damage to electricity infrastructure by calling 1850 372 999," it said.
In the event of a power cut:
Check your local area on ESB's PowerCheck here.
Met Éireann is warning of further stormy conditions, thundery downpours and further flooding.
Part 2: A spell of heavy and locally thundery rain over the north will clear to heavy squally showers with the risk of hail or thundery downpours leading to flooding locally. Also some damage and coastal flooding possible. Lowest temperatures tonight 3 to 7 degrees.— Met Éireann (@MetEireann) January 2, 2018
Update 7.38pm: Storm Eleanor: 50,000 ESB customers without power amid flooding and high winds
ESB has said approximately 50,000 customers are without power as Storm Eleanor brings floods and high winds to the country.
Mayo, Leitrim and Sligo appear to be worst hit with some of the largest outages in Westport, Ballina, Carrick-on-Shannon and Manorhamilton.
There has been flooding in Bantry, Middleton and Cork city centre, as well as on Merchant's Quay in Limerick.
Check your local area on ESB's PowerCheck here.
Met Éireann is reporting poor driving conditions in Connacht and the midlands as the storm tracks eastwards.
The forecaster has also recorded winds of up to 139km/hr.
Graph showing wind speeds and maximum gust at Mace head equivalent to 139 km/hr. pic.twitter.com/MNOp2Zmyl2— Met Éireann (@MetEireann) January 2, 2018
Update 6.36pm: Galway city centre has been hit by serious flooding as a result of Storm Eleanor.
The docks area of the city is impassable due to rising flood waters and Salthill Prom has been closed.
In County Cork, emergency services are dealing with flooding in Bantry town.
Roads around Bantry now fairly clear, lots of surface water and debris, caution advised. High tide 05:20 tomorrow, mind where you park @CorkSafetyAlert @aaroadwatch @SouthernStarIRL pic.twitter.com/PIkWvUWswP— Bantry Fire Brigade (@BantryFire) January 2, 2018
There are also reports of flooding in Midleton and on Union Quay in Cork city.
Met Éireann has reported gusts of almost 140 kilometres per hour at Mace Head in Co Galway.
A status Orange alert remains in place for much of the country as the storm moves across Ireland this evening.
Update on storm Eleanor:
Highest gust recorded so far at Mace Head Galway at 75 kts per hour at 5pm this evening. There will be flooding in places and damaging gusts are expected resulting in hazardous driving conditions as the storm continues its track eastwards.— Met Éireann (@MetEireann) January 2, 2018
Met Éireann is warning that Storm Eleanor will move in off the Atlantic this afternoon and will move very quickly across the country this evening.
Tonight will turn stormy with strong gale to force winds over Munster and Leinster.
A status orange wind warning is in place for Munster, Leinster and Galway.
"Southwest to west winds of mean speeds 65 to 80 km/h, gusting to 110 to 130 km/h., are expected," it said.
There is a risk of coastal flooding with very high seas along coastal coasts.
A spell of heavy and locally thundery rain in the east and north will track northeastwards with the risk of flooding locally.
Elsewhere heavy showers with the risk of thundery downpours.
Strong to gale force & squally SW winds over Muns & Lein, veering W this eve. w/ some v severe & damaging gusts & v high seas on Atl. coasts. A spell of heavy&loc. thundery rain in E&N will track NE w/ risk of local flooding. Elsewhere heavy showers w/ risk of thundery downpours.— Met Éireann (@MetEireann) January 2, 2018
There is also a yellow rainfall warning for Connacht and Donegal.
"Some thundery downpours expected in places this afternoon and early evening with falls of 20 to 25 mm in some parts," Met Éireann said.
The warnings are in place from 4pm to 10pm this evening.
Tomorrow will be windy and showery with strong winds.
Top temperatures for Wednesday between 7C and 10C with many showers, some with hail and thunder.