Wildfires raging in the heart of Canada’s oil sands region in Alberta showed no signs of abating, as they moved northeast toward the province of Saskatchewan amid efforts to re-evacuate people who had fled to oil-sands camps at risk of being cut off from the spreading blaze.

The fires, spurred by dry and windy weather conditions, have grown by nearly two-thirds since Friday, covering close to 400,000 acres, Alberta’s provincial government said Sunday. The fire’s large and spreading range means firefighters can only try to direct the blaze away from populated areas rather than extinguish it. And without a major rainfall, that likely won’t happen for months, officials have said.

Faced with that prospect, officials planned to evacuate about 6,000 people from areas north of Fort McMurray in northern Alberta either by car or air, Alberta Premier Rachel Notley said in a news conference Saturday. A convoy of 30 trucks carrying equipment and supplies started to move from south of Fort McMurray to the north of the city to support various industrial facilities in that area, the province said.

About 25,000 residents of the nearly 80,000 who had left the affected area initially fled north of the city to seek shelter at oil-sands worker camps and other facilities. Those camps are running out of supplies, and the evacuees were being directed south, where evacuation centers have been set up in larger cities such as Edmonton, Alberta’s capital, and Calgary.

“The fire is very dangerous and the end is not in sight,” Ralph Goodale, Canada’s public safety minister said Sunday on CTV Question Period, a Canadian news program.