ESB Networks says it has new faults over north Donegal as a thunder and lightning storm moves across the county.
There have been faults in Creeslough, north Inishowen and Glenveagh.
More snow showers are on their way tonight, say forecasters.
Donegal County Council gritting lorries are being deployed.
However Gardai are appealing to motorists to take extreme care on roads tonight and over the weekend.