Open this photo in gallery:

Smoke from the Mine Creek wildfire burning between Hope and Merritt, B.C., on Wednesday. The Fraser Valley Regional District declared a state of local emergency because of the blaze.HO/The Canadian Press

A semi-truck on fire has closed the Coquihalla Highway between Hope and Merritt, just hours after the key route to and from British Columbia’s Lower Mainland reopened following a two-day closure due to a wind-fuelled wildfire.

The province’s driver information service, DriveBC, issued an update on social media at 6:10 p.m. Friday saying the southbound lanes of the route were closed, followed by an update at 6:26 p.m. saying it was closed in both directions.

The route had just reopened after towering flames forced its closure for several days, and with the wildfire still burning, the Transportation Ministry says drivers can expect the status of the highway to change again on short notice.

The Fraser Valley Regional District has declared a state of local emergency due to the blaze, known as the Mine Creek wildfire, and issued evacuation orders for the Coquihalla Lakes Lodge and the Coquihalla Summit Snowmobile Club.

A state of local emergency is also in effect across the Cariboo Regional District, where residents of the community of Anahim Lake and surrounding areas have been told to leave immediately due to the threat of two encroaching wildfires.

Western Canada shrouded in smoke as hot, dry weather fuels new wildfires

The BC Wildfire Service says the Beef Creek wildfire has grown to more than 100 square kilometres, while the Dusty Lake fire spans 53 square kilometres.

Evacuees have been told to head east along Highway 20 to Williams Lake, where they can register to receive help at the Cariboo Memorial Recreation Complex.

The BC Wildfire Service says an incoming weather system is expected to bring little rain but an increased chance of lightning and gusty winds, raising the fire risk.

It says in Friday’s provincial situation report that wildfire smoke was expected to hang around for the next 48 hours until an upper low moves in from the Pacific.

The lingering smoke may temporarily affect the safe operation of firefighting aircraft, the service adds.

Wildfire ash is accelerating glacier melt in the Canadian Rockies

“Smoke alters local weather patterns by acting much like cloud cover, reducing the amount of sunlight that reaches the ground and helping humidity levels to remain a little higher. Wind speed and direction are also affected by smoke.”

A special air quality statement is in effect for most of B.C., with the exception of Vancouver Island, Haida Gwaii, Prince Rupert and the northwestern corner of the province.

“Consider reducing or rescheduling outdoor sports, activities and events. You may experience mild and common symptoms such as eye, nose and throat irritation, headaches or a mild cough,” the weather office says in its bulletin.

There are about 140 active wildfires across B.C., with more than 50 classified as burning out of control.