About 22,000 customers are still without power following a massive weekend storm that hit Metro Vancouver and British Columbia's South Coast, at one point leaving hundreds of thousands without electricity.

Power outages continue in Surrey, Burnaby and Vancouver, but BC Hydro says it hopes to get power restored to all customers affected by the weekend storm by the end of Monday.

According to BC Hydro, more than 320 power line technicians are out working to restore power. Repair crews from all across the province have been brought in to help with the work.

BC Hydro has also announced that many planned maintenance outages in the Lower Mainland and at Langford, near Victoria, will be postponed.

Earlier, crews were able to restore power to another 100,000 customers, including in downtown Vancouver, overnight Sunday.

Capilano University in North Vancouver will be closed for the day because its IT system is not working properly.

Power remains out at many intersections in Metro Vancouver and drivers are reminded to use the four-way stop procedure, which means treating all malfunctioning traffic lights as stop signs.

Environment Canada is warning more heavy rain is expected on Monday night as a cold front stalls over the region.

"The highest amounts will be over northern parts of Metro Vancouver and the Fraser Valley near the mountains with up to a total of 50 mm expected. Amounts for Howe Sound may reach 80 mm," said the Environment Canada alert.

Worst outages ever seen

An estimated 500,000 customers lost electricity after high winds knocked trees and branches down onto power lines on Saturday.

Traffic lights were still not working on Monday morning at many Metro Vancouver intersections, following Saturday's windstorm. (Farrah Merali/CBC)

"It was unlike anything we have seen before," said BC Hydro spokeswoman Simi Heer.

Vancouver's deputy city manager, Sadhu Johnston, said it could take weeks to fully clean up after Saturday's vicious windstorm. Johnston said the region's severe drought likely played a factor in the high number of trees that were blown down.

Arborists have also said many trees came down in the wind because they still had all their summer leaves.

The BC Hydro website was only partially functional as of 6 a.m. PT Monday, but customers can get updates on Twitter from @bchydro or by calling 1-888-POWER-ON.

A spokesperson said the website crashed because of the high volume of users on Saturday and the company has been working all weekend to restore the service.

911 jammed with unnecessary calls

After the BC Hydro website went down, many people called 911 looking for information, jamming the emergency service with unnecessary calls.

"911 can't answer questions about outages. Pls call 1-888-POWERON; follow @bchydro Help keep lines free for emergencies," said a tweet from @E-Comm911info.

Vancouver's director of emergency operations Daniel Stevens said if an even bigger catastrophe hits, everything could go offline so individuals should make plans to be self-sufficient for at least 72 hours.

"In a large event, the fire department and other first responders will be overwhelmed and will only be able to respond to priority calls, and all of the services that we get day to day from the less priority calls will be triaged. so it could be days until we get that kind of response," said Stevens.

"So the message is take care of yourself, plan and have some supplies. Develop a plan at home, where are you going to meet your family and put some supplies together, make a grab and go kit."

The city's deputy manager said it will review how it handled the storm and update its emergency plans accordingly.

"We ramped up quite quickly. We had the emergency operations centre fired up within minutes of the extreme wind coming in," said Johnston.

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