A key highway that connects Yukon and northern British Columbia to the rest of the province is now threatened by the huge Donnie Creek wildfire as the blaze chews through woodlands south of Fort Nelson, B.C.

The Peace River Regional District has posted an evacuation alert for a section of the Alaska Highway as out-of-control flames creep within two kilometres of the route.

The affected area is along a 160-kilometre stretch of the highway between Fort Nelson and Fort St. John. The city of Fort St. John is about 380 kilometres south of Fort Nelson, near the B.C.-Alberta border.

If the 4,875-square-kilometre blaze cuts the highway, residents north of Fort Nelson could face a more than 1,700-kilometre detour via highways 37 and 16 if they need to travel south by main roads.

Little rain from recent storms reached the Donnie Creek blaze Tuesday, but downpours around Dawson Creek, B.C., calmed the nearly 200-square-kilometre Kiskatinaw wildfire, which remains out of control and within a few kilometres of the community of Tumbler Ridge, which was evacuated six days ago.

The B.C. Wildfire Service (BCWFS) reports more than 80 active wildfires across the province Wednesday morning, with 37 ranked as out of control.

One of those has charred just over two square kilometres of trees on a steep hillside above the only highway linking Port Alberni, Tofino and Ucluelet to the rest of Vancouver Island, and officials say safety concerns could keep Highway 4 closed to full use until at least June 24.

There is a chance the highway could open on a limited basis by this weekend.

"In the days ahead, the Minister of Transportation will be looking to open Highway 4 using a single-lane, alternating traffic system," said Bowinn Ma, the minister of emergency management and climate readiness, during a Wednesday media briefing.

A lengthy detour is being used to allow people and supplies to reach the stranded communities, but the narrow route is only meant to be used for essential travel.

B.C. fire crews could soon have help battling the blazes around the province. During Wednesday's media briefing, Cliff Chapman, the director of wildfire operations for the BCWFS, said the service has requested support from an incident management team from the United States this weekend.

"Incident management teams are highly-trained, highly-certified personnel with usually years of experience that come in and take command of a large-scale fire that is challenging our efforts and our resources," Chapman said. "So this incident management team will come. We will put them onto one of our priority fires, and it will give us the ability to rest one of our own incident management teams."

Chapman said there are six incident management teams in B.C. and noted that "they are all going on their second or third tour of duty already this year, which is abnormal relative to many years in the past 20 years."

Meanwhile, Environment Canada has posted air quality statements for northeastern B.C., in the Fort Nelson, Peace River and Prince George regions, advising that wildfire smoke will blanket those areas for at least the next day or two.

The chief of the Doig River First Nation near Fort Nelson said the Donnie Creek fire has claimed a handful of trapline cabins, and his members are working to protect others.

Chief Trevor Makadahay said Tuesday that his community is as ready as it can be to evacuate if winds push flames from the north.

Residents, especially elders, are staying indoors and using air purifiers to cope with the heavy smoke blanketing the area, he said.

Rob Fraser, the mayor of the Northern Rockies Regional Municipality, said if the Donnie Creek fire does shut down the Alaska Highway, the closure would affect Fort Nelson in multiple ways.

"Everything comes to Fort Nelson by the highway, so it impacts groceries, it impacts fuel, it impacts medical supplies, it impacts people who need to get out of the community in order to get medical attention just because there [are] no specialists in the community," he said Wednesday morning on CBC's Daybreak North.

"There is a way to get [to Fort Nelson]," Fraser added. "You have to go all the way up into the Northwest Territories, Fort Simpson, and then back down Highway 77, which adds many, many hours to the trip and puts us at the end of the line."