The 19 firefighters who died after being trapped by an Arizona wildfire in late June were only about 600 yards from a designated safety zone at a ranch, according to a task force formed by the Arizona State Forestry Division to investigate the firefighters' deaths.

And when the crew — the Granite Mountain Hotshots, an elite group of firefighters based in Prescott, Ariz. — was forced to deploy their emergency shelters, "a Very Large Airtanker was on station over the fire waiting to drop retardant as soon as the crew's location was determined," the forestry service's investigation found.

But it wasn't until later that the firefighters' whereabouts would be discovered, a delay that seems to be rooted in a prolonged gap in communication that day. The fire killed all but one member of the team; the sole survivor was on lookout duty elsewhere.

The Serious Accident Investigation Report that was released Saturday provides new insight into a tragic event that brought a shocking loss of life. But the investigative team's report also acknowledges a lack of available information, particularly about the final half-hour of the firefighters' lives.

The report identifies several points of possible confusion in the effort to combat the Yarnell Hill fire, which was started by lightning on June 28, from weather reports that may have been misunderstood to radio communications that the investigators deem "challenging."

The report's 116 pages are based on visits to the scene of the fire, as well as interviews and audio and video files that were recorded about the fire.

The Granite Mountain firefighters were fully trained and qualified, and they "followed all standards and guidelines," the report concludes. Of the broader effort, the report found that the incident commanders made reasonable decisions.

The report's authors "found no indication of negligence, reckless actions, or violations of policy or protocol," they write.

But the report also notes that the Yarnell Hill area "had not experienced wildfire in over 45 years. It was primed to burn because of extreme drought, decadent chaparral, and above average cured grass loadings."

With abundant fuel and favorable weather conditions, the fire quickly grew into a complex blaze, with some of the most striking developments occurring on the afternoon of Sunday, June 30, when the Granite Mountain team sought refuge. By that point, efforts to save structures in the area had been abandoned.

"There is a gap of over 30 minutes in the information available for the Granite Mountain [hotshot crew]," according to the report. "From 1604 until 1637, the Team cannot verify communications from the crew, and we have almost no direct information for them."

The report's authors add, with italics to stress their point, "There is much that cannot be known about the crew's decisions and actions prior to their entrapment and fire shelter deployment at around 1642."

The 19 members of the crew were found about a mile from their last known location. Other emergency personnel had assumed that the Granite Mountain team would remain in "the black" — a portion of the rough landscape that the fire had already burned. But they left that area and traveled over an unburned section, heading to a safety zone at the Boulder Springs Ranch.

Around the same time, a thunderstorm in the area brought winds that both sped up the fire's spread rate and changed its direction — the second 90-degree shift in direction in a day, according to the report.

Investigators believe the firefighters were cut off from their emergency escape route by one of the fire's two heads that had begun moving in their direction, propelled by strong winds.

In the moments before they were overtaken by the fire, the blaze was moving toward the firefighters at a speed of an estimated 10-12 mph, according to a briefing video accompanying the release.

"It is estimated that the time between the sighting of the fire front from the deployment site to the time the fire reached the deployment site was less than two minutes," according to the video.

From the report, here's what seems to have been the final radio exchange with the Granite Mountain team and an Aerial Supervision Module:

Granite Mountain Division Alpha: "Yeah, I'm here with Granite Mountain Hotshots, our escape route has been cut off. We are preparing a deployment site, and we are burning out around ourselves in the brush and I'll give you a call when we are under the sh- the shelters."

ASM2: "Okay copy that. So you're on the South side of the fire then?"

Granite Mountain Division Alpha: "Affirm!"

A DC-10 tanker that was in the air near the region was ordered to get closer to where the firefighters might be, and await a detailed location. But seven attempts to reach the team failed in the next four minutes. By then, medical and rescue teams were also in motion, trying to find the team. When they were found in the box canyon, none had survived.

"They were deploying fire shelters when the fire overtook them," according to the report. "Temperatures exceeded 2,000 degrees Fahrenheit, and the deployment site was not survivable."

The Granite Mountain team members were killed just two days after the blaze began as a small fire on a remote hillside. Because of the difficult terrain and what was seen at as "minimal fire activity or spread potential," a full suppression effort was put off until the next day, according to the report. But conditions brought changes to the blaze that rapidly escalated its size and strength.

The panel dedicated its report to the memory of those who lost their lives that day.

The firefighters' deaths brought an outpouring of grief in Prescott that included a memorial service at which Vice President Joseph Biden spoke. It also spurred disagreements in Prescott, over firefighters' survivor benefits and job classifications.

In addition to those concerns, releasing reports on destructive wildfires is also a sensitive issue, as they could contain information that might be used in lawsuits against local governments or agencies.

"The National Interagency Fire Center... now urges investigators to withhold some findings from the public, and to avoid analyzing whether crews violated fundamental fire-line rules," reports The Arizona Republic.

The Arizona Forestry's task force is also posting its report on the Wildland Fire Lessons Learned website.

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