The findings made by a team of fire experts were released Saturday. The 120-page report cited improperly programmed radios, vague updates, and a 33-minute communication blackout just before the flames trapped the men.
According to the report, a large air tanker carrying fire retardant was hovering overhead at the moment the firefighters were killed. Officials were reportedly waiting for an update on their location.
On June 30, the Prescott Fire Department's 20-member Granite Mountain Hotshots team was called to help battle a 2,000-acre wildfire burning in the town of Yarnell in central Arizona. Nineteen of the firefighters were killed.
Among those killed were two local firefighters: Kevin Woyjeck of Seal Beach and Christopher MacKenzie from the San Jacinto Valley.
The report stated that the day went according to routine until the wind shifted, pushing a wall of fire that had been receding from the firefighters all day back toward them.
After that, the command center lost track of the 19 men. Without telling command, and despite the weather warning, the firefighters left the safety of a burned ridge and dropped into a densely vegetated basin surrounded by mountains on three sides. The command center believed the firefighters had decided to wait out the weather change in the safety zone.
Command did not find out the men were surrounded by flames until five minutes before they deployed their emergency shelters. Without guidance from headquarters or their lookout, who had left after warning the crew, the men had bushwhacked into a canyon that soon turned into a bowl of fire. The topography whipped up 70-foot flames, producing 2,000 degree heat. Fire shelters, always a dreaded last resort, start to melt at 1,200 degrees.
The firefighters may have failed to communicate during that crucial half hour because they entered a dead zone, or because they were wary of overloading the radio channels.
The sole surviving member of the hotshot team was the lookout. Brendan McDonough was a half mile away watching the fire behavior when the flames suddenly whipped 180 degrees around and cut off their escape route. No details of how he managed to escape the fire have been released.
Though the report points to multiple failures, investigators did not consider whether the deaths could have been avoided.
Some family members were angered that the report didn't draw stronger conclusions about why the men died and recommend changes. David Turbyfill interrupted a news conference on Saturday to shame officials for not providing his 27-year-old son Travis with the protection he needed to survive as the flames swept over him. He said the shelter Travis died in had not been improved in 13 years.
"This report is fairly conclusive that the fire shelters are a total disaster. Policies, as they may be, need to change," he said.
Investigators recommended that Arizona officials review their communications procedures and look into new technologies, including GPS, that might help track firefighters during chaotic situations.
The Yarnell Hill fire is listed as the deadliest wildfire involving firefighters in the United States for at least 30 years.
The Associated Press contributed to this report.