Snow drifts of up to five metres have caused major problems for emergency crews working to restore power to homes in Northern Ireland.
Northern Ireland Electricity said that around 2,000 homes are still without electricity and two helicopters have been deployed to help crews reach isolated areas.
It could be several days before services in remote areas are restored, with repair crews being assisted by workers from the Republic of Ireland and Scotland.
Sara McClintock from NIE said: "Unfortunately small numbers of customers will be off overnight in isolated rural areas.
"These are areas that we have still been unable to reach by road.
"We have been using a helicopter today to deliver teams and limited equipment in these areas and we have commissioned an additional helicopter for tomorrow to help us access the faults."
Emergency oxygen supplies were earlier airlifted to an elderly man trapped by heavy snow in the Newtownabbey area in Co Antrim.
He had no electricity and dwindling supplies and a police helicopter was used to deliver more cylinders to the 79-year-old at his home.
A police spokesman said: "Several attempts were made by local police to get to the man, but the road was impassable. The police helicopter was then tasked to airlift the casualty to hospital.
"However, the man was unable to be moved as he was so weak and frail, so the helicopter was then used to deliver vital oxygen."
Several roads were blocked and driving conditions were tough on many other roads.
At one stage, water supplies were cut off and an RAF helicopter transported mountain rescue teams to the most vulnerable.