A status red snow and ice warning is in place nationwide - with people being warned to stay indoors from 4PM.
Last night Met Eireann updated the red alert to include all counties, until tomorrow afternoon.
Further snow showers are expected this morning, with Storm Emma bringing blizzard like conditions this afternoon
All schools, colleges and third level institutions will be closed today and tomorrow.
Gardai say that roads are dangerous in some areas this morning following snowfall and freezing temperatures.
In Ballina the Foxford to Ballina Road is again very dangerous and sheltered spots are described as lethal.
In the Tuam area, conditions are also described as very poor, while again parts of the Castlerea area are dangerous.
There are poor conditions on the N17 between Tubbercurry and Collooney and also around Roscommon Town and on the N61 and N63 roads going into the town. Gardai in Galway are advising extreme caution in Galway city following heavy snowfall overnight.
Bus Eireann services will not operate today, while Irish Rail services will wind down today between midday and 2pm, with no services then until at least midday on Friday. As regards flights at Ireland West Airport Knock, the Aer Lingus service to and from London Gatwick has been cancelled for today. At this stage Ryanair expects to operate a full schedule but the situation is fluid and passengers are advised to check with their airline before travelling.