Canadian officials have started evacuating 8,000 people by air from work camps north of a city devastated by a massive wildfire that has grown to cover 85,000 hectares.
Emergency teams hope to move thousands more from Fort McMurray, Alberta, in a highway convoy if it is safe from the huge blaze.
More than 80,000 people have emptied Fort McMurray in the heart of Canada's oil sands, authorities said.
The Alberta government, which has declared a state of emergency, said more than 1,100 firefighters, 145 helicopters, 138 pieces of heavy equipment and 22 air tankers were fighting 49 wildfires, with seven considered out of control.
Chad Morrison of AB Wildfire, manager of wildfire prevention, said the fire is still growing but is moving away from Fort McMurray and its rate of growth has slowed.
About 25,000 evacuees moved north in the hours after Tuesday's mandatory evacuation, where oil sands work camps were converted to house people.
But the bulk of the more than 80,000 evacuees fled south to Edmonton and elsewhere, and officials are moving everyone south where they aim to have better support for the displaced.
Officials had flown 4,000 evacuees to Edmonton and Calgary by Thursday evening and expected to fly 4,000 more by the end of the day.
They hope the highway will become safe enough on Friday to move the remaining people out via the south. A helicopter will lead the evacuation convoy to make sure the highway is safe, and will pass through Fort McMurray where the fire has destroyed 1,600 homes and other buildings.
Alberta premier Rachel Notley said the first convoy will be 400 vehicles and officials will see how that goes.
There have been no injuries or deaths in the province from the fires, and Ms Notley said financial support will be provided to Albertans and cash cards may be made available for evacuated residents.
The Alberta government has declared a province-wide fire ban in an effort to reduce the risk of more blazes in a region that is very hot and dry.
"It is a very rare step," environment minister Shannon Phillips said. She added that ignoring the ban could lead to fines.
Fort McMurray is surrounded by wilderness and is Canada's main oil sands town. Despite the size of the town and its importance to the Canadian economy, there are essentially only two ways out by car. The region has the third largest reserves of oil in the world behind Saudi Arabia and Venezuela.
Aided by high winds, scorching heat and low humidity, the fire grew from 75 square kilometres on Tuesday to 100 square kilometres on Wednesday, but by Thursday it was almost nine times that - at 850 square kilometres.
The fire remained wrapped around the western and southern edges of the city. No rain clouds are expected around Fort McMurray until late on Saturday, with 40% chance of showers, according to online forecasts by Environment Canada.
Unseasonably hot temperatures combined with dry conditions have transformed the boreal forest in much of Alberta into a tinder box. Mr Morrison said officials are investigating the cause of the fire but he said it started in a remote forested area and could have been lightning.
A combination of factors conspired to make this wildfire especially ferocious, said Bill Patzert, a climatologist at Nasa's Jet Propulsion Laboratory in California. The El Nino global weather system brought Alberta a mild winter and low snowpack, he said. Mr Patzert said the flames sparked at a time between the snowy season and before springtime rains that turn the landscape green, making the region especially vulnerable to wildfire.
"In a way, it's a perfect storm. It's been warm, it's been dry and windy. It's the in-between period before you're in the full bloom of spring."