The finding, revealed in an official investigative report on the fire that was released on Saturday, encapsulates one of several unanswered questions surrounding the event, the deadliest day for firefighters since the Sept. 11 terrorist attacks, and perhaps the most vexing: Why did the men end up where they did?
While the report, the result of a three-month investigation, said there had been poor communication between the firefighters and the command center — some of it because of spotty equipment — it did not assign any blame for the tragedy and said proper procedures were followed.
“Nobody will ever know how the crew actually saw their situation, the options they considered or what motivated their actions,” the report said.
Investigators said they could offer only educated guesses, based on where the firefighters wound up.
The crew left the village of Yarnell, where the fire started, and traveled parallel to the flames, building a fire line — a type of trench devoid of any vegetation or other fuel — as a way to contain the blaze.
The firefighters traveled southeast near a ridge top, the report said, before descending toward a ranch in Yarnell, perhaps in an attempt to reposition themselves and get back to fighting the flames.
The report said the crew “did not perceive excessive risk.” They died about 600 yards from their destination. Having hiked the same route the crew took that day, the investigators concluded that the ranch probably looked closer than it was. The area was crowded with dried vegetation and big granite boulders, causing the men to travel at about half their regular speed, the report said.
As the men descended from the ridge, they gradually lost sight of the fire. As they entered the basin at the base of the mountain, flames emerged ahead of them, leaving them no option to escape, the report said. Based on the speed the fire was moving — 10 to 12 miles per hour — investigators estimate that two minutes passed between when the firefighters spotted the approaching flames and when they deployed their emergency shelters.
The deployment site was “not survivable,” the investigators said, because there was too much unburned vegetation there, causing the flames to sweep over the men. Investigators said the temperature of the fire climbed above 2,000 degrees, well above the 1,200 degrees that the fire shelters are designed to withstand.
The wildfire began on June 28 and quickly grew into an inferno that destroyed more than 100 structures and burned 13 square miles before it was fully contained 12 days later. A crucial focus of the investigation was the 33 minutes during which there was no recorded radio communication between the crew and anyone else working the fire, allowing the men to shift locations without anyone knowing where they were going or the command center being able to steer them away from danger.
During a news conference here on Saturday, Jim Karels, the Florida state forester, who was in charge of the investigative team, said the team could not tell whether the firefighters could have been saved if there had been no lapse in communication between the crew and the commanders.
“The outcome is something we can’t determine,” Mr. Karels said.
Relatives of the fallen firefighters were briefed on the report earlier in the day, before its release to the news media and the public.
The findings were emotional for the families and the disaster’s sole survivor, Brendan McDonough, 21. Mr. McDonough, the 20th member of the Hotshots crew, was serving as the lookout on another mountain that day. When he saw the fire shift direction, he left his position because he no longer felt it would be safe for him to remain.
Some families traveled from as far as Illinois and Tennessee for the briefing. Others, like Dan Parker, a firefighter whose son, Wade, was among the 19 who died, came from neighboring Chino Valley to be beside others who might understand what he has felt in recent months.
The investigators said they were able to determine that as the flames closed in on the 19, none of them ran or abandoned the tight formation or procedures they had practiced so many times in drills — entering their shelters in order from the least to the most experienced, rookies at the center, veterans on the edges. Seven of the fallen firefighters were found inside fully deployed shelters. Four were inside shelters that had been mostly deployed, and eight were in partially deployed shelters.
The investigators pored through radio transmissions, logs from safety briefings, statements from people involved in finding the group once its superintendent, Eric Marsh, delivered his last, ominous message: “The Granite Mountain Hotshots are deploying their fire shelters.”