Snow, sleet and storm force winds have caused disruption in Northern Ireland, leaving tens of thousands of homes without power and travel delays.
The Roads Service said more than 300 staff in 130 gritters were on stand-by to salt main roads last night.
Snow drifts of up to 15.7in (40cm) have been reported.
"Most routes have been salted three times overnight with snow ploughing necessary on many routes," a spokesman said.
The adverse weather conditions have also cast doubt over tonight's World Cup clash between Northern Ireland and Russia at Windsor Park.
Kick-off is due to take place at 7.45pm.
The Irish Football Association said it would make a decision after a pitch inspection and assessment of the South Belfast stadium later this morning.
If the match does not go ahead tonight, the IFA is looking at the possibility of playing it tomorrow.