A downed tree is the cause of a partial power outage in Fort Smith that began Wednesday night, says the Northwest Territories Power Corporation.

The power went out late Wednesday but repair crews were delayed getting to the community because of the overnight closure of Highway 5.

The highway was closed due to a forest fire in Wood Buffalo National Park. The road reopened Thursday morning.

Parts of Fort Smith have been without electricity for more than 12 hours.

Crews are now working to restore power.