People "should not venture out" during expected blizzard-like conditions tomorrow
Met Éireann has issued a status red snow-ice warning for the entire country, effective from tonight until Friday afternoon.
The Taoiseach Leo Varadkar has called on the public to stay safe and to heed warnings from Met Éireann and State agencies.
Officials have warned that people should not venture outside during expected 'blizzard-like conditions' tomorrow.
Schools & third level institutions across the country will not open for the rest of the week, while major transport disruption is expected.
UPDATE: Status red has now been issued for all counties with immediate effect. All schools, third level institutions and colleges of further education will be closed tomorrow and Friday #stormemma— Richard Bruton (@RichardbrutonTD) February 28, 2018
After an earlier status red warning was issued for Leinster & Munster for Thursday afternoon onwards, that was later upgraded for the entire country.
It is effective from 11pm tonight until 3pm Friday.
Speaking following a meeting of the National Emergency Coordination Taskforce earlier, Mr Varadkar said: "Storm Emma is coming up from the south and will meet polar air from the east - it'll give rise to heavy snowfalls, combined with strong winds of up to 100 kph.
"These conditions will start at approximately 4pm tomorrow and spread northwards across Munster and Leinster.
"Having considered this serious warning, the National Emergency Coordination Group has advised that people should not venture out of doors when the red level warning is in place".
Mr Varadkar said he has directed "that the full resources of the State should make every effort to ensure the safety and welfare of our people."
And he said that employers should assess "whether it's safe or even necessary for them to open - and whether it is safe for their staff to travel to and from work".
The Defence Forces has deployed 60 army personnel and 16 vehicles to support local authorities.
The deployments took place in Kilkenny, Wexford, Waterford, Cork, Kerry, Kildare, Dublin and Donegal.
The 3rd Battalion, based in Kilkenny had vehicles and personnel assisting with the transport of dialysis patients and nursing staff to and from Wexford and Waterford Hospitals.
They also provided support to the meals on wheels service in Kilkenny, and assisted the local council in clearing snow and ice from key transport hubs.
In Cork, troops were deployed from Collins Barracks in support of the HSE, driving palliative care nurses to their patients in Cork City as well as assisting with an ambulance service in Cork County, and transporting salt and grit for the county council road clearing operations.
Troops from the Defence Forces Training Centre in Kildare transported nursing staff to a local nursing home and also provided a snowplough to Kildare County Council for use in Newbridge, Athgarvan, Kilcullen and the Curragh.
In Dublin, troops from Cathal Brugha Barracks provided support to a local hospice to ensure palliative care nurses could reach patients, while also ensuring medications were delivered to Crumlin Children’s Hospital.
The Defence Forces also provided mobility assistance to An Garda Síochána in Donegal, Cork and Kerry.
The Defence Forces say personnel remain on stand-by around the country for support that may be required tonight and tomorrow.
After an earlier meeting, officials said people in the areas affected by tomorrow's red warnings should not venture out while the warnings are in effect.
Sean Hogan, Chair if the National Emergency Coordination Group warning of further snowfall and high winds from 16:00 tomorrow with serious blizzard conditions and Red Alert in place. People should not venture out in Red areas during these warnings pic.twitter.com/LHdkXxo3Uk— OEP (@emergencyIE) February 28, 2018
Hundreds of schools in counties such as Dublin, Kildare, Louth, Wicklow and Meath were closed on Wednesday after the status red weather warning was issued.
In a statement on Wednesday afternoon, the Department of Education said: "Given the disruption to transport and the safety risks arising, most particularly in relation to the ability to get home safely before blizzard like conditions hit Munster and Leinster, all schools, third level institutions, colleges and centres of further education in red areas will be closed tomorrow and Friday.
"In relation to Connaught and Ulster decisions on school closures will be made individually depending on the circumstances in their area. The situation in Connaught and Ulster will be kept under review."
Meanwhile, social welfare recipients who were due payments on Friday will be able to collect their payments from Thursday.
The Department of Social Welfare said it has made arrangements with An Post and banks to provide Friday payments earlier than usual "for customers who may need to collect their payment earlier in areas impacted by the severe weather".
However, the payments will also be available for collection once the bad weather passes.
The Government has already confirmed it will double the fuel allowance for this week, although some people might not get their payments until next week or the week after due to different payment dates.
An Post says it will work to make sure post offices within the red zone will, where possible, be open between 9.00am and 1.00pm on Thursday.
However, all letter and parcel services in Dublin, Louth, Wicklow, Kildare and Meath have been suspended until further notice.
The Dáil and Seanad have been adjourned for this week, with Leinster House set to reopen on Monday morning.
There is also major transport disruption expected tomorrow amid widespread service cancellations.
Dublin Bus says none of its services will be operating on Thursday.
There will also be no Bus Éireann services in Leinster and Munster.
Irish Rail services will wind down from noon on Thursday, and will remain closed for at least 24 hours.
Luas will be running limited services on Thursday morning.
But from 12.00pm, trams will be withdrawn and a full suspension will be in effect from 2.00pm.
Airline passengers have also faced widespread disruption, with hundreds of flights affected.
Additional reporting: Jack Quann