FORT MCMURRAY, Alberta » Canadian officials began evacuating 8,000 people from work camps north of devastated Fort McMurray by air today and hoped to move thousands more via a highway convoy Friday if it is safe from a massive wildfire raging in Alberta that has grown to 210,035 acres.

More than 80,000 people have emptied Fort McMurray in the heart of Canada’s oil sands, authorities said.

The Alberta government, which declared a state of emergency, said more than 1,100 firefighters, 145 helicopters, 138 pieces of heavy equipment and 22 air tankers were fighting a total of 49 wildfires, with seven considered out of control. Chad Morrison with AB Wildfire, manager of wildfire prevention, said the fire continued to grow but is moving away from Fort McMurray and the rate of its 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 can get better support services.

Officials had flown 4,000 evacuees to Edmonton and Calgary by this evening and expected to fly 4,000 more by the end of the day. They hoped the highway would become safe enough on Friday to move the remaining people out via the south. It wasn’t safe Thursday. A helicopter will lead the evacuation convoy on Friday morning to make sure the highway is safe. It will pass through Fort McMurray where the fire has torched 1,600 homes and other buildings.

Alberta Premier Rachel Notley said the first convoy will be 400 vehicles and officials would see how that goes.

There have been no injuries or death in the province from the fires. Notley said financial support will be provided to Albertans and that cash cards may be made available for evacuated residents.

The Alberta government also declared a province-wide fire ban in an effort to reduce the risk of more blazes in a province that is very hot and dry.

Morrison said rain is needed.

“Let me be clear: air tankers are not going to stop this fire,” he said. “It is going to continue to push through these dry conditions until we actually get some significant rain.”

The fire remained wrapped around the western and southern edges of the city. No rain clouds were expected around Fort McMurray until late Saturday, with 40 percent chance of showers, according to online forecasts by Environment Canada.

Notley said she didn’t know how much better the evacuation could have been when asked if ample warning was given to residents, noting that in 48 hours more than 80,000 people were evacuated from a town that essentially has two roads out of it.

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 via 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 29 square miles Tuesday to 38.6 square miles on Wednesday, but by today it was almost nine times that — at 328.2 square miles. That’s an area roughly the size of Calgary — Alberta’s largest city.

Unseasonably hot temperatures combined with dry conditions have transformed the boreal forest in much of Alberta into a tinder box. Morrison said they are investigating the cause of the fire but he said it started in a remote forested area and said it 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. 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,” Patzert said. “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.”

The fire is driving one of the largest evacuations in North America in recent memory, said Bill Stewart, co-director of the University of California’s Center for Fire Research and Outreach at the University of California, Berkeley.

With few exceptions in the United States, an entire town hasn’t been threatened on this scale for more than 100 years, he said.

“You could add five times the number of firefighters, but you can’t get all the embers,” he said. “There’s no way to put out every ember flying over firefighters’ heads.”

Fort McMurray resident Fahed Labek, whose relatives from war-torn Syria recently migrated to northern Alberta as refugees, said his family has escaped one fire for another. Labek fled the encroaching wildfire two days ago with family members, who arrived in Canada in late February.

Labek, who made it to Edmonton after a harrowing journey, is concerned the refugees are enduring additional trauma after leaving the Middle East. But he said he’s taking solace in the helpfulness of Canadians now assisting the tens of thousands of forest fire evacuees.

The fire has dealt a blow to the region’s crude production, with companies curtailing production or stopping altogether. Notley, the province premier, said the infrastructure for oil and gas production remains largely unaffected. What’s slowing down production is that their employees are not there, she said.

The airport only suffered minor damage because of the “herculean’” efforts of firefighters, said Scott Long of the Alberta Emergency Management Agency. Firefighters have focused on protecting key infrastructure like the water treatment plant, the hospital and the airport. Crews water bombed the city today.