Gardai have warned motorists to avoid making all but essential journeys because of continuing snow and low temperatures in western areas.
Temperatures were expected to plummet for a second night in a row, making road travel hazardous this morning.
In Galway, the north of the county was most seriously affected, while the city escaped with light snowfalls from lunchtime yesterday which did not settle.
However, several minor road accidents were reported on routes in Connemara and east Galway, and snow was falling heavily last night.
The Oranmore-Craughwell-Loughrea section of the main Galway-Dublin road was hazardous in parts from mid-afternoon yesterday.
In Mayo, frost and snow made travelling difficult, particularly on secondary routes.
The 5.45 p.m. Citylink bus service from Galway to Dublin was cancelled as conditions worsened in the midlands.
The severe weather alert extending to the west is expected to last until the weekend, according to Met Eireann.
