A huge blaze lit up the early-morning sky in High River as flames engulfed a housing complex under construction in the town south of Calgary.

Crews are still at the scene of the fire that largely destroyed the facility being built at Macleod Trail and Eighth Street. 

High River fire crews called their counterparts in Okotoks for assistance just after 5 a.m., an official said. The Okotoks Fire Department sent one aerial ladder truck to help battle the blaze.

"The building was fully involved at the time, flames shooting at least 40, 50 feet in the air, and the fire department was kind of standing back from it, shooting water on it from a high arc," High River Online reporter Russell Skeet told CBC News.

There have been no reports of injuries. The adjacent Soderberg House, home to 22 seniors, was evacuated as a precaution, the town said in a release.

The new Medicine Tree Manor and the attached West Winds Lodge were being reconstructed after they devastated by the 2013 floods.

Skeet said many High River seniors are still displaced and were waiting to move in to the new building.

"This is a huge blow for this community," he said. 

The $13-million project was just months from completion, said Lauren Ingalls, CEO of the Foothills Foundation, which owns and operates the seniors facilities.

"I think right now we're all pretty much in a state of shock," she said. "The entire building will most likely be demolished."

It's believed the fire started in the west-central wing, she said. 

Alberta Health Services (AHS) issued a precautionary air quality advisory for High River because of the smoky conditions caused by the fire. 

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A seniors' housing facility under construction in High River was gutted by fire on Tuesday morning. (Russell Skeet/High River Online )

high river fire

Crews battle a major blaze at a construction site in High River early Tuesday morning. (Russell Skeet/High River Online )

fire high river seniors lodge

Fire crews from Okotoks assisted the High River Fire Department to get the blaze under control. (Russell Skeet/High River Online )