According to Canadian officials, the huge wildfire which devastated the oil town of Fort McMurray could double in size over the next 24 hours.
The fire now covers an area larger than New York City and is being fanned by winds and feeding on dry vegetation.
The flames are moving away from Fort McMurray, most of whose inhabitants have reached safety.
Many are still stuck north of Fort McMurray and evacuations by road and air are resuming.
More than 80,000 people were evacuated from the city earlier this week.
Thousands of people have been airlifted out but a mass convoy evacuating people from oil worker camps in the north was halted on May 6 as huge flames flanked the road.
At least 2,500 made it through the flame-damaged city and small convoys resumed early on Saturday. Another 4,000 people are also due to be flown out.
There is growing concern over the air quality for those still north, CBC reported.
The provincial government said on May 6 that the fire had grown to 386 sq miles.
Wildfire prevention manager Chad Morrison said there was a “high potential that the fire could double in size” by the end of Saturday, May 7.
However, he added that it would expand into a more remote forested area north-east of Fort McMurray.
Dry conditions and 27C heat were expected during the day, but cooler temperatures would prevail and there was a possibility of rain on May 8 and 9.
No deaths or injuries have been reported.
Alberta provincial government has declared a state of emergency and will provide C$100 million ($77 million) in cash to evacuees.
According to the Canadian government, more than 1,000 fire fighters and 150 helicopters, 295 pieces of heavy equipment and 27 aircraft tankers have been deployed.
Despite the evacuation order, the Royal Canadian Mounted Police (RCMP) said they found an elderly man and a family of five in Fort McMurray. They were led to safety.