Damage to the electrical network Thursday and Friday was concentrated in the southern and eastern areas of the country, operator Northern Ireland Electricity said.
Snow drifts of up to 15.7 inches were reported, The Belfast Telegraph said, and the Roads Service reported 300 employees in 130 trucks were on stand-by Thursday to salt roads.
"Most routes have been salted three times overnight, with snow plowing necessary on many routes," a Road Service spokesman said Friday.
The snow was expected to disrupt travel across northern parts of the United Kingdom, while the national weather office has issued 15 flood warnings in the southwest, the BBC reported.
Torrential overnight rain caused the partial collapse of a home in the southern England area of Cornwall that had been caught in a landslide. Rescue workers are searching for a woman who resided in the building, which had been converted into apartments.
In northern regions of England and in Scotland, as much as 16 inches of snow was expected. Snow was predicted to continue over the weekend.
Heavy snowfall in Scotland this week made driving dangerous and led to the closing of more than 100 schools.
The combination of high winds, rain and snow could create a "real witches brew" for drivers, said Darron Burness, head of operations for the British motoring association AA.
Met Office forecaster Andrew Sibley said March was set to be the coldest in decades, with no sign of spring.