VIDEO: Drone captures moment of northern Ontario building explosion

SUDBURY - Drone footage by Sudbury area resident Nick Lavoie captured the moment a Capreol building exploded on Jan. 24, injuring three volunteer firefighters from the Capreol station.

Lavoie’s video, captured before 8 p.m. on Jan. 24, shows three firefighters in front of the building when it explodes, which sent sections of the building’s front exterior falling in their vicinity.

As of this morning, a City of Greater Sudbury spokesperson said one firefighter has been discharged from the hospital overnight, and two firefighters remained in hospital for observation.

When they were taken to hospital during the evening of Jan. 24, Assistant Deputy Fire Chief Craig Lawrence said the three volunteer firefighters received non-life-threatening injuries and were taken to Health Sciences North in stable condition.

Firefighters were blasting water through the front door of the building when another door to the building was opened and "there was a smoke explosion, knocking the firefighters in front of the building to the ground," Assistant Deputy Fire Chief Craig Lawrence said.

The website ScienceDirect describes smoke explosions as being similar to the more familiar "backdraft," though the two phenomena differ in a key way. As made famous in the movie of the same name, a backdraft occurs when a large amount of ventilation is suddenly introduced into a closed-room fire environment. The influx of incoming air mixed with the fuel in the space, creating a fireball that can be catastrophic.

A smoke explosion, the article states, is a similar, but not as well understood, phenomenon.

"Anecdotal evidence supports a different phenomenon in which a closed compartment suddenly erupts in flames breaking glass and even causing structural damage without a vent ever being open," states the 2013 paper by Charles M. Fleischmann and ZhiJian Chen of the University of Canterbury in Christchurch, New Zealand.

Greater Sudbury Police Services have joined the Ontario Fire Marshal’s Office by investigating the fire to determine the cause of the Jan. 24 fire.

Local detectives are also working in collaboration with the Ministry of Labour due to the injuries sustained by the three volunteer firefighters.

The fire forced the city to reroute Gova route No. 105. 

A man who lived in the apartment building right next to the building where the fire began told Sudbury.com about his narrow escape. 

Stephane Fex said he heard crackling through the wall of his apartment around 7:30 p.m. this evening and knew he was listening to the sound of a fire. He immediately cleared his home of people and pets.

"And within 15 minutes of getting out, the entire (neighbouring) building was in flames and it exploded," he told Sudbury.com this evening. He described the explosion as "catastrophic."

"All the windows, walls, caved out at the same time. It was crazy," said Fex, who has lived in his building for two years. "Everyone got to safety before the explosion happened, luckily."

The four residents of Fex's building, as well as the five residents of the apartment building where the fire started, are all accounted for and uninjured. Fex and his neighbours are displaced "as a temporary precaution," Assistant Deputy Fire Chief Craig Lawrence said.

The four-plex ended up burning to the ground, while Fex's neighbouring apartment building suffered some fire damage to an exterior wall. The building was without power last night, and Lawrence expects it also suffered structural damage. It's unclear when the building's residents will be allowed back in.

Tyler Clarke is a reporter from Sudbury.com.