OTTAWA - Wildfires sweeping through Canada's Alberta province on Tuesday destroyed a remote lodge used to house hundreds of oil workers and threatened other camps north of the blaze-hit city of Fort McMurray, a top official said.

Thousands of people had been evacuated overnight from the lodges, about 50 kilometers (30 miles) north of the blaze-hit city, as the fires spread and intensified, Alberta Premier Rachel Notley told a press conference.

The Black Sands lodge with 665 rooms was destroyed. Two others on the same road with a total of 4,000 rooms were at risk. "Yesterday morning we anticipated a very active fire day and," she said, "that's exactly what we got." "We expect fire growth at many of these camps today," she added.

In Fort McMurray, two explosions damaged 10 homes. Ensuing spot fires were quickly put out and nobody was injured.

Eight new fires sprung up over the previous 24 hours, bringing to 19 the total number burning in the province. Five of those were burning out of control.

The largest of these, in and around Fort McMurray, has grown to 355,000 hectares (877.000 acres), which represents "significant growth from yesterday," Notley said.

Overnight, the evacuation of the camps was ordered as westerly winds pushed the forest fire closer to Syncrude and Suncor facilities.

"All nonessential staff, about 8,000 people, were evacuated, mostly to the north," Notley said.

Air quality in the north due to smoke remains at more than three times the acceptable levels, posing a risk to firefighters and delaying both repairs to damaged Fort McMurray infrastructure and the eventual return of tens of thousands of residents.