Transport chiefs admit "everybody was taken by surprise" by the "flash flood of snow" which brought chaos to the roads at the weekend.
However, angry motorists who were caught out by the snow criticised the lack of advance warning, with one TD saying the country was treated to the "red side of an orange warning".
While Met Éireann maintains its yellow warning was appropriate, forecaster Gerry Murphy said that "due to the fact that this snowfall fell over a relatively short period on a Sunday afternoon and evening when a lot of people were travelling, it did cause a significant impact".
Met Éireann had issued a rainfall warning for Sunday but said the rain would turn to "sleet and snow in places as temperatures drop to between 1C and 5C". Crucially it had predicted "significant accumulations will be largely confined to higher ground, however, with just light coverings at lower levels".
However, the heavy snowfall brought chaos to parts of the midlands and the east, with motorways brought to a standstill and roads left impassable.
Sean O'Neill, director of communications for Transport Infrastructure Ireland, which oversees the country's motorway network, described it as "almost a flash flood of snow".
He said the severity of the snow was unexpected and "everybody was taken by surprise". He said the decision by gardaí to close sections of motorway meant it was more difficult to get gritters out - just as thousands of motorists were returning to Dublin after the weekend.
"There was massive disruption and it was difficult for the gritters to get out. What you won't hear about is the lives that were saved and the cars that didn't crash because of the guards' decision," he added.
However, some of those motorists caught out by the snow were angry at the lack of warning.
It took Louise O'Connor, her husband and their five-month-old baby Grace seven hours to travel from Cork to Dublin. At one stage on the M7 it took them an hour to travel just 100-200 metres and they thought they would have to spend Sunday night in their car.
"The information didn't get out in time. We were expecting rain, not snow," she told RTÉ Radio.
Fine Gael TD for Kildare South, Martin Heydon, said he and his young family were also caught up in the "mayhem" of the heavy snow. He said questions need to be answered as to why the severe weather wasn't predicted.
He and his three children, the youngest of whom is just nine months old, were travelling from Naas to their home outside Kilcullen on Sunday afternoon. The journey would normally take just 20 minutes but ended up taking two-and-a-half hours.
Speaking to the Irish Independent, he said: "We were at a children's birthday party in Naas. People were just running for their cars trying to get home.
"The kids were crying for the last hour-and-a-half (of the journey) but you have no way of stopping, you just had to keep going."
He said conditions on the M7 were particularly bad.
"By the time the ploughs got out there were already accumulations on the M7. We were going southbound and we were absolutely crawling, but northbound was a lot worse."
Mr Heydon said that while Met Éireann's colour-coded weather warning system is "very positive", "the problem is that when people don't get one they think everything is fine".
"Met Éireann tweeted at 11am that there would be sleet and snow, and the forecast was for high ground. What we got was on the red side of an orange warning," he said.
Meanwhile, poor weather conditions are believed to have been the cause of a number of road traffic collisions across the mid-west and west yesterday.
Several incidents were reported on the M18, M17, M7 and M6. All the incidents are understood to have been single-vehicle crashes that occurred following heavy downpours of hail.
Mr O'Neill said gritters would be out in force across the country again this week.
"Met Éireann is reporting that temperatures will dip later in the week so we will have our winter operations in full course," he said.
Met Éireann is predicting a cold and very unsettled week ahead with spells of heavy rain, some wintry falls and frost.