PRESCOTT, Ariz. (AP) — An erratic wildfire driven by ferocious and shifting winds curled around the location of a team of Arizona Hotshot firefighters, cutting off their access to a safety zone and creating a death trap that quickly consumed them, two fire officials have confirmed based on a map of how the tragedy unfolded compiled by The Associated Press.

The map shows that the 19 highly trained Hotshots were just over a quarter of a mile northwest of the safety zone using chain saws, axes and other gear to build a line between the wildfire and the small town of Yarnell on Sunday. But the fire, which was northeast of the team, suddenly changed directions after the winds shifted nearly 180 degrees and cut off their access to the safety zone, a large ranch property.

The AP confirmed the location of the fire crew, their safety zone and the fire’s advance based on interviews with people who knew what happened. After building the map, its accuracy was confirmed by Dan Ware, a spokesman for the crews battling the blaze, and Prescott Fire spokesman Wade Ward.

The circumstances of the firefighters’ deaths have been known for days but Friday’s confirmation offers the most detailed picture about their location and how close to safety they appeared to be.

Officials said the 20th member of the Prescott-based Granite Mountain Hotshots, who served as a lookout for the Hotshot crew and whose exact location during the fire is unclear, was on a hilltop and warned the team that erratic winds had shifted the fire’s direction and they were in danger.

The Hotshot crew was working to build a line to keep the fire from getting into Yarnell, working on the southeast end of the fire with the wind blowing generally to the northeast. But a thunderstorm that developed north of the fire caused the winds to shift so they were coming from the north, blowing the fire right toward the Hotshots.

The crew had designated a ranch house and its surrounding cleared area as their safety zone, a spot they should be able to reach if things went bad. But the fire moved too fast for them to reach the ranch house, killing the 19 firefighters; the lookout, 21-year-old Brendan McDonough, was able to make it to safety.

A national team of investigators is working to understand more about the firefighters’ deaths, visiting the site where they were killed, interviewing McDonough, and examining radio logs and weather conditions. They are expected to release some findings soon, but it will take much longer for a full report.

"Apparently their escape route was inadequate," said Carl Seielstad, an associate research professor and fire and fuels program manager at the University of Montana’s National Center for Landscape Fire Analysis.

Seielstad, also a former longtime smokejumper and hotshot who has lost colleagues in previous fires, said it’s still too early to say whether the Hotshots made any mistakes but that the investigation certainly will identify violations in protocol by virtue of the deaths themselves.

"All of these fatalities associated with fire shelter deployments have commonalities that relate to sudden and unexpected changes in fire behavior, that firefighters were in a compromising position and failed to recognize the danger they were in until it was too late. And after the fact when we look back, we always think, ‘They should have expected this,"’ he said. "These investigations are always awkward for other firefighters because they sort of imply that mistakes were made, although maybe mistakes were made."

Eric Lawton, a school board member in Yarnell, knows the area where the wildfire is and said its giant boulders, thick stands of scrub oak and manzanita would have posed high difficulty for the firefighters. The terrain would have impeded how fast they could move in the face of danger, he said.

"Knowing the area, you couldn’t scramble out of there if you had to," Lawton said. "I don’t care about special meterologist on site or any of that, they had no chance."

The lightning-caused wildfire was 90 percent contained Friday, after destroying more than 100 homes in Yarnell and burning about 13 square miles. Fire bosses have begun sending some crews home, and power and gas companies were working to restore service in Yarnell.

Residents of the evacuated community of Peeples Valley were allowed to return home Thursday, but about 700 people who live in Yarnell will have to endure more time out of their homes. Earlier in the week it was hoped they could go home by Saturday, but that’s been pushed back perhaps as far as Monday evening.

The ruins of some homes continued to smolder Friday, and cracks inside the many large boulders around town can hold hot embers for days. Crews need to be sure the town has cooled completely to avoid new flare-ups, said Jim Whittington, information officer for the Southwest Incident Management Team. Power lines and burned poles need to be replaced, and power cut to destroyed homes. Hundreds of propane tanks also have to be either removed or tested for leaks and repaired if necessary.

Sens. John McCain and Jeff Flake were planning to meet with Yarnell residents on Friday and speak to members of the media afterward.

A memorial service for the firefighters is set for Tuesday, with Vice President Joe Biden expected to attend.

Autopsies of the firefighters showed they all died of either burns or inhalation issues, or a combination of both. Their bodies, in Phoenix for autopsies, are set to be returned home to Prescott on Sunday in a 75-mile procession. Each firefighter will be in a hearse, accompanied by motorcycle escorts, honor guard members and American flags.

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Myers reported from Prescott, Christie reported from Phoenix. Associated Press writers Paul Davenport in Phoenix, Allen Breed in Prescott, Felicia Fonseca in Flagstaff and Martin Di Caro in Washington contributed to this report.