The fire that killed four members of the Canadian military and injured dozens of others on Saturday spread with alarming speed, accounts suggest.
It broke out in a grassy training area at a base in the province of Alberta and spread rapidly due to strong winds.
"The fire was 1km (0.6 miles) away when the wind shifted," said Maj-Gen Wade Rutland, commander of the 1st Canadian Division of the Canadian Armed Forces. "It is not normal for a fire to move a kilometre in 30 to 60 seconds."
Prime Minister Mark Carney described it as "one of the worst tragedies for the forces on Canadian soil in peacetime". Officials have ruled out the possibility of "any terrorist activity" being to blame for the fire.
The blaze began at about 16:00 (22:00 GMT) on Saturday at Canadian Forces Base Wainwright, one of the country's busiest military training bases.
The BBC has confirmed that Sgt Morgan Wong, Pte Shaun Farrell, Pte Aidan Goulding and Pte Hayden Lykkemark have died.
Of the 39 injured people receiving care in hospital, at least 19 are in a critical condition.
Warren Thirsk, an emergency department doctor at the Royal Alexandra Hospital, told Canadian broadcaster CBC that the number of patients involved in the incident had "completely overwhelmed" healthcare facilities in Wainwright.
Tributes are being paid to the servicemen who died.
Patricia Farrell, the mother of Shaun Farrell, wrote on Facebook that it was "with heavy hearts that we share the news that our son, Shaun Farrell, has passed away to be with our Heavenly Father".
Wong received a tribute from the Loyal Edmonton Regiment, of which he was part. The regiment was "deeply saddened", it wrote in a Facebook post of its own. It sent "heartfelt condolences to [the group's] families, friends, and fellow soldiers".
The mother of Goulding, Sonia Monk, said her late son was an exceptional athlete and a natural leader. "He was always the guy who kept everybody's spirits up," she told CBC. "He really was the light of my life."
In account of Saturday's events, Rutland told reporters that members of the infantry had been conducting "high-intensity combat training with live munitions" at a grenade range and attack range.
He told reporters that officials knew about the fire on the base for several hours, but it was decided that training "could carry on for a certain amount of time".
"I spoke to my commander last night, and he said within 30 seconds to a minute they saw no fire, and then there was a fire right on top of them," Rutland said.
Rutland said it was not yet known what exactly caused the fire.
Some witnesses had said they had heard explosions, fuelling speculation that oil and gas infrastructure may have been hit and sparked the fire. But Rutland said authorities "do not believe this [incident] to be a result of any oil and gas infrastructure".
The Canadian Armed Forces has said that "while the incident remains under investigation, at this time, there are no indications that it was the result of any terrorist activity".
Forecasters had issued a wind warning on Saturday for large parts of Alberta, predicting wind gusts of up to 90km/h (66mph), Canadian broadcaster CBS said.
According to Rutland, the investigation may take at least a month.
Wainwright, about 130 miles east of Edmonton, Alberta's capital, is one of the main bases used by the Canadian military for live-fire training exercises, and it houses troops from Canada and allied countries.
About 690 military personnel and 300 civilian workers are on site on a typical day.
