MET Eireann faced a backlash today after more than twice as much rain fell than had been predicted.
Forecasters were yesterday saying that between 20mm and 40mm would fall in the Dublin region, but the eventual deluge far exceeded these amounts.
One weather station, Casement Aerodrome, recorded rainfall in the region of 90mm over several hours.
As a result, homes and businesses throughout the capital were not ready for what came.
Dublin City Council told the Herald today that it was informed by Met Eireann to expect heavy rain but the downpours were "worse than expected".
"The emergency plan kicked in last night at 8pm when it became apparent there was more rain than expected," a spokesman said.
"In fairness to Met Eireann, they had been warning about it all week but it was worse than we had anticipated," he added.
"It was unprecedented rain - there's not much you can do about that."
But Gerald Fleming of Met Eireann said today that forecasters had been warning about the potential for very heavy rain for six or seven days.
"We were aware of it six or seven days in advance, the potential at least. What happened was a big high pressure build-up over Eastern Europe," Mr Fleming said.
He added that when that happens, the weather front would normally pass across and the rain would move on. However, on this occasion, the front "got stuck" over Ireland. He added that there was more to come, with a station just outside Wexford recorded 80mm this morning.
"Some of that will be moving on up to Wicklow and Dublin in the next four to five hours, probably about 10mm likely," he said. "It's not a huge amount ... but on top of everything else it could cause some problems."
East and west Wicklow were most at risk, said Mr Fleming, adding that the amount that fell over three to four hours yesterday was "almost unprecedented".
The last significant deluge to hit the East coast was over three years ago.
But last night's downpours shattered those records.