Blizzard conditions not seen since the big snows of 1982 are expected across the south and east of Ireland on Thursday.
Meteorologists are expecting “serious and life-threatening conditions” from 4pm on Thursday until midday on Friday with driving snow and zero visibility in places.
National Emergency Coordination Group chairman Sean Hogan said it would be "suicidal" to go driving in the areas affected by Storm Emma which is due on Thursday afternoon.
“If you have driving wind and snow and visibility that is very poor, you may become disorientated and get lost very quickly,” he said.
“Unfortunately we had cases of people dying in the cold spell in 2010 who were outdoors. There is an obvious issue about driving. Do not be out there from 4pm (Thursday evening). It is primarily a safety concern that we have for people and their safety.”
Winds of 100 km/h will cause snow to swirl and settle in drifts as Storm Emma coming up from the Bay of Biscay meets cold Siberian air. The worst affected counties will be those along the south and east coasts.
The status red warning will be place in Munster and Leinster from 4pm on Thursday to 12pm on Friday. There will also be snow over most of the rest of the country during the same time period, but it will not as intense as in the south and east.
Met Éireann forecaster Evelyn Cusack warned there will be "more or less zero visibility" during the snowstorm because of the snow which is granular in nature and will blow around easily. "Meteorologically, it is very dangerous snow," she said.
Snowfall on Tuesday night and Wednesday morning was worse than predicted with 16cms of snow falling at Baldonnel Airport overnight causing the upgrading of the weather warning from orange to the highest level red. Between 5 and 6cms were expected.
Ms Cusack said the heavy snow on Thursday will be on top of the snow which will have already have fallen and will stay on the ground because of the frigid temperatures. Those temperatures will fall to minus 7 on Wednesday night. It will remain around freezing on Thursday though the wind chill factor will make it feel well below freezing.
Storm Emma will pass over the country by Friday afternoon. Ms Cusack said it looks like the storm will gradually pull up warmer air which should displace the Siberian air.
She said there remains the possibility of snow lying through Friday and Saturday with isolated snow showers over the weekend.
On Sunday it looks like returning to milder conditions with highs of between 4 and 9 degrees. There will be rain at times, but also a good deal of dry weather.
