Met Eireann said conditions for travellers would be more dangerous today compared to the past three days.
Motorists have been urged to heed safety warnings this weekend with sub-zero temperatures, ice and freezing fog to prevail.
Gardai reiterated that journeys should not be undertaken in stricken areas unless absolutely necessary.
Drivers have also been warned against being lulled into a false sense of security about road conditions as thawing is not due to begin until late tonight or tomorrow.
Snow showers are expected to die out in the east and midlands, but temperatures will remain as low as minus 3 degrees inland.
Mr John Doyle of Met Eireann said: "The worst of the snow may be over, but the worst of the ice and frost is not."
The Automobile Association said it had one of its busiest days of the year yesterday with more than 2,000 calls to its help-line and 530 emergency repairs jobs carried out by 5 p.m.
Temperatures in Dublin failed to rise above freezing all day. As they dropped again last night, concern was expressed for the welfare of dozens of people sleeping rough on city streets.
The Simon Community and Focus Ireland said Dublin Corporation's efforts to tackle homelessness in the winter period were insufficient.
The two groups called for more emergency accommodation. Meanwhile, the funeral took place yesterday of Ms Sarah Gallagher (92), from Annagry, Co Donegal, who froze to death outside her home on Wednesday.
Age Action Ireland has called on people to check on the wellbeing of elderly neighbours or relatives who are living alone. A spokesman for the group said elderly people should ensure they had at least one hot meal a day and should consider sleeping in the same room as their heating.
Thursday night was the coldest this year, with temperatures dropping to minus 16 degrees in Foxford, Co Mayo. More than seven inches of snow were recorded in parts of Connacht and Ulster.
According to Met Eireann, the last time snow fell as heavily was five years ago and before that during the freak storms of 1982.
The freezing conditions caused more disruption to Bus Eireann commuters yesterday with all services to the west and north-west cancelled.
Severe weather conditions on the US east coast have forced the cancellation of five Aer Lingus flights to New York and Boston today; flights from the US also will be disrupted.
The flights affected are: EI 105 Dublin to New York/JFK at noon; EI 111 Shannon to New York/JFK at 1.20 p.m.; EI 107 Dublin/Shannon to New York/ Newark at 3 p.m.; EI 137 Dublin to Boston at 2.40 p.m. and EI 135 Shannon to Boston at 4.50 p.m.
Passengers booked on these flights should contact Aer Lingus at 01-8868888 to make alternative travel arrangements.