Investigators are now on scene at Edmonton’s Roxy Theatre, where an early morning fire tore through the building, leaving only a couple walls standing.

Fire crews first arrived at the Roxy on 124th Street around 4 a.m. after getting a call that the theatre's smoke detector was going off.

When they arrived on scene just four minutes later, they found heavy smoke pouring out of the back of the theatre and called a second alarm.

At its peak, about 50 firefighters were working to contain the flames while police, EMS and Edmonton Transit provided support. However, structural damage to the building and the intensity of the blaze prevented crews from entering the building to fight the fire.

Deputy Fire Chief Barry Lamb

"It's a tough old fire," said Deputy Fire Chief Barry Lamb of the Roxy Theatre blaze. (CBC)

"For safety reasons, we had to fight the fire from outside," said deputy fire chief Barry Lamb on Tuesday morning. "It's a tough old fire."

By 6:30 a.m., the theatre's roof, front and some of its walls had collapsed.

The fire was finally declared under control just before 8 a.m.

District chief Dave Matwichuk said a team of 16 firefighters will remain on scene putting out hot spots through the afternoon while investigators begin sorting through the rubble.

Matwichuk said buildings to the north and south of the Roxy Theatre have some smoke and water damage, but crews were able to stop the fire from spreading. There are no estimates yet for the total cost of the damage.

“Obviously there’s still a lot of work to be done at this site,” Matwichuk said.

Traffic along 124th Street and 107th Avenue was diverted for hours Tuesday morning while firefighters put out the flames. Most have now been reopened but 124th Street is still closed between 107th and 108th Avenue.

Power was also shut off to homes and businesses within two or three blocks of the Roxy for several hours, but has now been restored to all but the immediately neighbouring buildings.

‘Tragic loss to community’

Deputy Fire Chief Lamb was among the first to speak out about the theatre’s history and importance Tuesday morning.

Lamb said he felt a "twinge" when he realized Edmonton was likely losing one of its landmark buildings.

"It is a big part of our city," he said.

Roxy Theatre fire

Three hours after arriving on scene, fire crews continued to douse the Roxy Theatre in water. Officials say the building to the south will likely sustain some water damage. (Lydia Neufeld/CBC)

Several employees from Theatre Network — the company that owned and operated the Roxy — also made their way to the theatre as soon as they heard about the fire.

“I was the first one after the firefighters on site just in time to see the walls collapse and everything come down,” said production manager Scott Peters.

"A lot of things go through your head, you know,” added marketing direct Taylor Chadwick. “We had a show (Cheerleader!) that was set to start performances tonight, actually," he said.

"We're sort of speechless right now."

Fire a loss 'beyond words'

The Roxy first opened in 1938 as a movie theatre. It was converted to a live performance facility in 1989.

Members of Edmonton's theatre community have been mourning the loss of the space, which had become an integral part of the city's performing arts scene.

Roxy theatre fire

The historic Roxy Theatre as it appears on Google Streetview (left), and what it looks like Tuesday morning (Lydia Neufeld/CBC)

A statement from Adam Kuss, artistic director of the Walterdale Theatre, called the Roxy an institution.

"On behalf of the Walterdale Theatre, our hearts go out to the Theatre Network family and all the artists that have ever graced the stage at the Roxy," he wrote.

"We are deeply saddened — this is a loss for the Edmonton theatre community that is beyond words."

Many people have already taken to social media to start planning efforts to rebuild the historic theatre.