Thousands of homes on the Shetland Islands off Scotland's northeast coast were without power in freezing temperatures on Wednesday after "significant" snowfall, the electricity provider said.
The Scottish and Southern Electricity Networks (SSEN) said engineers were working to restore supplies to about 2,800 homes but that full restoration was only likely by the end of the week.
Temperatures on Shetland plunged to -10 Celsius (14 degrees Fahrenheit) on Tuesday.
On the Scottish mainland, the mercury dipped to -17C in the Highlands town of Braemar.
"Engineers continue to work in extremely challenging conditions and have restored power to 1,000 properties in Unst, Gutcher and parts of Yell by repairing the main 33 kilovolt network," an SSEN spokesman said.
More engineers are due to arrive in Shetland on the ferry from the city of Aberdeen on Wednesday to help restore the power supply.
Emma Macdonald, the leader of Shetland Islands Council, said wet and heavy snow had brought down power lines and poles.
"We don't normally get much snow, we get a lot of wind and gales, and it has had a significant impact," she said.
"We have so many lines down and people could be without electricity until the end of the week."
"We are a resilient community and are often cut off during the winter if the ferry doesn't run. We do all pull together."
The islands' main Sumburgh Airport was also forced to close after its air traffic control's secondary radar communications were hit by the weather.
Highlands and Islands Airports Ltd said it had also been hit by power outages and that only emergency flights only had been operating.
A manager at the St Magnus Bay hotel on the north of The Mainland island of Shetland said it was using a generator to warm the premises and had opened its doors to people in need.
"We have many elderly people living in our area and many of them do not have access to power or gas," she told AFP.
"We have been taking soup and filling up flasks of hot water for those in need."
Some people were burning peat to keep their homes warm, she said.