VANCOUVER - Crews continue to repair fallen transformers and restring hydro lines after last week's powerful windstorm in southwestern British Columbia, but officials say some customers will remain without power for several more days.

BC Hydro said it has restored power to more than 550,000 customers since the windstorm hit Thursday and about 44,000 customers were still waiting on Sunday.

Public Safety Minister Mike Farnworth said emergency operations centres have been activated in affected areas and warming centres have been opened in many communities.

“I would ask all British Columbians in affected areas to ensure that they have supplies and plans in place to remain safe during this incident, and to please check in on neighbours, particularly those in a vulnerable situation,” Farnworth said in a statement.

Farnworth reminded members of the public to stay at least 10 metres away from downed power lines, which should be considered live. It's also important to use generators safely and never use portable generators, outdoor barbecues or camp stoves indoors, he said.

“I know that an extended power outage during the holiday season presents particular challenges for many. I want to ensure British Columbians that our government will continue to support BC Hydro as it works to safely restore power as quickly as possible,” Farnworth said.

BC Hydro has described the storm as one of the worst it has seen in 20 years. RCMP said it killed one woman in Duncan when a tree fell on her tent, while the storm also caused Nanaimo's water treatment plant to break down and destroyed a 30-metre section of White Rock's pier.

Vancouver Island and the Gulf Islands were among the hardest hit areas and hundreds of downed trees have left some roads impassable, which means BC Hydro has not been able to complete full damage assessments.

About 4,000 of its customers waiting for power are in the Lower Mainland and the Fraser Valley, and BC Hydro said it could take another three days before power is restored to rural areas.

Chris O'Riley, president and chief operations officer for BC Hydro, said Sunday the utility is hopeful that power will be restored to affected customers on the Lower Mainland by the end of the day on Monday. But Vancouver Island and the Gulf Islands will take more time, especially as crews deal with more remote, individual outages.

“Based on reports that are coming back from our field crews and the images you're sharing with us, we know that a number of communities are facing significant damage. We know how difficult prolonged outages can be,” O'Riley said in a video statement.

On Sunday, 81 line crews were tackling Vancouver Island, many of whom travelled from other parts of the province to help out, he said.

“On behalf of BC Hydro, we appreciate your continued support and your continued patience,” O'Riley said.