The military's top commander believes the main reason soldiers couldn't escape the deadly fire at CFB Wainwright is because of how quickly it tore across the training area.

Asked what barrier soldiers faced getting away from the fire, Chief of the Defence Staff Gen. Jennie Carignan suggested it spread too fast.

"So I think, this is mostly due to how fast the fire travelled," Carignan said in an interview on CBC's airing Sunday morning.

Carignan said investigators are now working on reconstructing the scene at different moments which is "going to reveal how it all happened." 'Immediate changes' not needed for training at CFB Wainwright following deadly fire: CDS Multiple investigations are underway to try and get to the bottom of why four soldiers were killed and 39 more injured on Saturday's fire at CFB Wainwright in eastern Alberta. Investigators are trying to find out what exactly caused the fire and why training was allowed to continue for hours.

Military officials have said the fire started because of training on an automatic grenade launcher range nearby, but the area was too dangerous for firefighters to enter. While the fire was being monitored, winds picked up and it quickly spread to where soldiers were training, officials said.

Carignan wouldn't say if firefighters were already at the training area or on their way when the fire reached the soldiers, citing that the investigation would provide more clarity.

"Our personnel on the ground did manage the casualty evacuations as the firefighters were dealing with the fire itself," Carignan told guest host David Common.

Training has resumed at the base. Carignan said at this point they haven't changed any procedures, but will if the investigations flag issues.

"For the moment, we have nothing that indicates that we need to make immediate changes," Carignan said.

The Canadian Forces Provost Marshal, Brig.-Gen. Vanessa Hanrahan, said at a news conference on Thursday the fire broke out in a "permanent danger zone." That designation means the area is always a no-go-zone because of ongoing hazards from live-fire exercises. Undetonated grenades or other ordinates could be on the ground and blow up if disturbed.

CFB Wainwright fire began on automatic grenade launcher range, military says The base's fire hall and range control — those responsible for enforcing safety standards across live-fire ranges — were monitoring the fire "throughout the day," Hanrahan said. But then when the wind got stronger, the fire got more intense and spread, she said.

The fire moved to where C company of the 3rd Battalion, Princess Patricia's Canadian Light Infantry (PPCLI), was doing live-fire training to prepare to deploy to Latvia this spring, the military said.

Asked if there was pressure for commanders to get this training done within a certain amount of time, Carignan said "a lot of things are going to be considered" as part of the investigation.

But she said there is a "considerable amount of time" before the spring deployment and leaders have the flexibility to "rearrange or reschedule depending on weather, depending on a lot of factors." Retired major Robert Parent was a PPCLI infantry officer and president of a past board of inquiry into a soldier's death. He said that, in retrospect, any incident could be prevented.

"I do not believe that in any way there should be a witch hunt conducted," Parent told CBC News.

"But the reality is that one decision at any time during this process would have avoided the final and tragic outcome. That's just reality." Parent said he spent three years at CFB Wainwright during his 34-year career, including participating in and running training exercises. He said he has extensive experience organizing, planning and supervising live-fire training including as a range safety officer.

Soldiers understand that there are inherent risks and dangers of the job — whether it's from weapons, the elements, training with armoured vehicles or jumping out of airplanes, Parent said.

But in the context of training, "we have systems and processes that mitigate that risk," he said.

How the deadly CFB Wainwright fire got so dangerous, so fast "No one goes out on a training exercise with the understanding that we may lose a soldier.… That's not the way it works." Parent said there were dry conditions that day at CFB Wainwright, a weather warning coming in and an active fire. Investigators will look at how all three of these elements came together to create this incident and what decisions were made on the ground, he said.

"Why wasn't the information not brought together so that the chain of command could have made an appropriate decision with relation to the degree of risk that the fire, the weather event and the conditions on the ground may have dictated?" he said.

Parent held the most senior role on the board of inquiry into military technician Kyle Sinclair's death in 2014 at CFB Petawawa.

He said a board of inquiry into what happened at CFB Wainwright will not say if the chain of command made mistakes or cast blame.

Instead, that inquiry's job is to flag weak points and processes in the system to make recommendations to prevent the same incident from happening again.

Parent said the inquiry might not start for more than a year because the military police investigation and civilian coroner's investigation are completed first so the board can look at those reports.