A massive clean-up operation was under way in Dublin yesterday after record rainfall brought chaos to the city.

Dejected Armagh GAA fans travelling from Croke Park on Saturday where their side was beaten by Wexford were among those caught up in the mass floodings when they returned to find their cars stranded.

The “monsoon-like” rainfall caused mass traffic congestion across the capital and the cancellation of a number of sports events.

Record levels of rainfall at 76.2mm for August were recorded at Dublin airport over the 24-hour period between Friday and Saturday night, according to Met Eireann.

This was more than the 73mm in 1986 in downpours associated with Hurricane Charlie.

Yesterday gardai warned motorists to avoid several routes around Dublin which had been made impassable as a result of the rain.

Flooding affected many parts of Leinster with a river bursting its banks in Laois and flooding reaching over two feet in some housing estates in Celbridge, Co Kildare.

Rail services were affected on Saturday night in north Dublin when a landslide blocked a train line south of Malahide.

Dublin City Council put in place its crisis management plan when the severity of the situation emerged.

Dublin fire brigade received some 800 calls over an eight hour period — equal to a Halloween night. Staff who had been on holidays were drafted in to help.

"The rainfall was completely freakish, it was of monsoon proportions. Even Met Eireann couldn’t forecast the particular weather front coming in until sometime on [Saturday] morning which was very late," said a spokesman for the local authority.

A spokesman for Dublin Fire Brigade said crews spent most of the night rescuing people from houses and cars.

"People would be ringing up saying their houses are flooded and there was water on the roads. People were trapped in cars and they needed to be rescued," he said.

The strength of the rainfall meant drains were being filled with water before they could be cleared, resulting in floods in a number of areas, said the council spokesman.

Members of the Civil Defence were also drafted in to help the fire brigade to pump water from buildings.

Yesterday, motorists were told to avoid the M50 as there was severe flooding on both the north and south bound lanes. The south bound part of the Port Tunnel, which had been closed, reopened yesterday afternoon and operated toll-free for a period in order to accommodate traffic coming from the north going to Croke Park.

A spokesman for Iarnrod Eireann said all services were operating as normal following disruptions on Saturday evening which stopped Darts from Howth Junction to Malahide and Howth.

The Maynooth line was also affected for a few hours after flooding at Broom Bridge. It was estimated that 5,000 rail passengers were affected as a result.

A group of 4,000 scouts at the Scouting Jamboree in Punchestown had to spend the Saturday night indoors after being removed by the Civil Defence to the major events centre on the site.

The 8am Stena Line sailing between Rosslare and Fishguard yesterday as cancelled due to the bad weather.

Both Leixlip and Maynooth also experienced flooding while in Co Laois the Ballyroan to Portlaoise Road was flooded at Cashel Cross after a river burst its banks.

The Tullamore Show in Co Offaly, which was due to take place today, was cancelled for the second year running due to the weather.

It is not yet known what the full extent or cost of the damage will be.

The agencies which tackled the flooding in Dublin — including the gardai, the National Roads Authority (NRA), the local authority and the Health Service Executive (HSE) — are to meet during the week to assess how the issue was addressed.

Dublin Lord Mayor Eibhlin Byrne conveyed her thanks to all the emergency services who dealt with the fall-out from yesterday’s extreme weather.

"This was an unprecedented and extreme weather event and it is great to hear that serious injury and fatality have been avoided," she said.

Meanwhile, a helicopter attempt to rescue an injured woman from near the summit of Croagh Patrick, Co Mayo, had to be abandoned on Saturday due to dense fog.

The woman, a 56-year-old from Co Kerry, who was making the climb for her first time and was accompanied by her husband, was eventually brought off the mountain by members of Mayo Mountain Rescue and transferred to hospital, with a broken ankle.