A catastrophic wildfire that has forced all 88,000 residents to flee Fort McMurray in Alberta, Canada exploded tenfold in size on Thursday, cutting off evacuees in camps and shelters north of the city.

The out-of-control blaze has burned down entire neighborhoods of Fort McMurray in Canada's energy heartland and forced a precautionary shutdown of some oil production, driving up global oil prices.

Three days after the residents were ordered to leave Fort McMurray, firefighters were still battling to protect homes, businesses and other structures from the flames. More than 1,600 structures, including hundreds of homes, have been destroyed.

Although the cause of the fire was unknown, officials said tinder-dry brush, low humidity and hot, gusting winds left crews unable to stop the massive conflagration.

The blaze, which erupted on Sunday, grew from 18,500 acres on Wednesday to some 210,000 acres Thursday, an area roughly 10 times the size of Manhattan.

"What people in that region have gone through in the last couple of days is literally hell on earth," Rona Ambrose, leader of the opposition Conservative Party and an Albertan, fighting back tears as she addressed the Canadian Parliament in Ottawa.

Fire has intermittently blocked the only route south toward major cities, so thousands of evacuees fled north toward oil camps and a few small settlements.

They found themselves stranded in makeshift shelters and on roadsides when the flames cut them off from Fort McMurray. Most of Alberta's oil sands facilities are north of the city and not in the path of the flames.

A government airlift of evacuees began from oil facility airstrips on Thursday. Canadian Natural Resources, meanwhile, said it airlifted about 2,600 people over the last 24 hours to Edmonton and Calgary, including its own workers, to make room for more evacuees.

Frightened evacuees north of the city took to Twitter, asking when they would be able to drive south and whether areas to the north were safe.

"We're just sitting in a camp praying to get out!! Give us answers!!! Please," Twitter user @jennimac780 told the regional government.

"We haven't forgotten about you and you're safe," the government said on Twitter.

Hundreds filled a community center on Thursday morning in Lac La Biche, a community about 170 miles (290 km) south of Fort McMurray. Many were second-round evacuees who were ordered to relocate from temporary refuges closer to Fort McMurray on Wednesday night as the flames grew.

Other people bunked down in a Lac La Biche high school, its gym converted to a used-clothing station for the evacuees.

Kirby Abo, who came from Fort McMurray with his wife and three children, said he worried that his job in a recycling depot may no longer exist when he returns home.

"I think it's going to be a ghost town for quite a while," he said.

The winds gave the city a brief reprieve on Thursday by driving the fire to the southeast, away from populated areas. But officials warned that the unpredictable weather could quickly shift again.

The winds pushed flames toward the local airport, which suffered minor damage and was open for limited non-commercial operations, officials said. A makeshift emergency operations center at the airport was evacuated for the second time in less than a day.

At least 640,000 barrels per day of crude output is offline, according to Reuters calculations, roughly 16 percent of Canada's crude production. The outage is expected to climb as major players in the region cut production. [O/R]

A Conoco Phillips spokeswoman said the Surmont oil sands project had been evacuated as a precaution because of potential highway closures. The fire was roughly 24 miles (38 km) north of Surmont on Thursday.

The forecast has called for cooler temperatures and a possibility of rain, offering hope that controlling the blaze could become easier.

Authorities said there had been no known casualties from the blaze itself, but fatalities were reported in at least one vehicle crash along the evacuation route.