The lone survivor of the Arizona wildfire that killed 19 firefighters was working as a lookout for the crew when conditions suddenly worsened and he narrowly escaped the inferno himself as he warned his colleagues to get out.
The "very distraught" survivor has been identified as Brendan McDonough, a member of the highly-trained Granite Mountain Hotshot Crew, according to the Prescott Fire Department.
McDonough, 21, was "acting as a lookout at the time for the crew," Prescott Fire Department spokesman Wade Ward told ABC News.
Ward said it is "very common" for crews to have a lookout at a higher location so that they can be in both radio and visual contact. He said that McDonough was on a hillside within a mile or two of the crew monitoring the situation.
When firefighters are involved in a situation, they have pre-determined "trigger points" that indicate to them that it is time to re-evaluate if the fire reaches the trigger points.
When conditions worsened, McDonough saw that his colleagues were in danger and warned them as his own trigger point was destroyed by the flames.
"He had radioed that his trigger point had been reached and so he radioed the crew and told them that he was leaving," Ward said. "As he was leaving, he had stated that the winds had changed so fast and picked up so fast that his trigger point was burned over within three minutes."
The elite team of firefighters was battling a raging wildfire in Yarnell, Ariz., when dry thunderstorms laced with strong, erratic winds shifted unexpectedly in the searing heat of the Southwest, likely creating the perfect storm that trapped and killed them, according to officials.
"He was warning them to get out," Ward said of McDonough. "They had made their plan to get out. They were attempting to reach their safety zone and get back to that point. He [McDonough] was picked up by a Blue Ridge Hotshot supervisor and was evacuated from the area and the crew attempted to get to their safety zone and they just couldn't outrun the fire. It changed that fast."
The wildfire killed 18 of 20 members of the Granite Mountain Hotshot Crew. The 19th dead firefighter was from another group. McDonough was the only survivor of Sunday's disaster.
Wade said that McDonough is "very distraught" and trying to figure out what happened.
"He's lost 19 of his best friends and co-workers and he's working through it the best that he can," Wade said. "He's being cared for not only by the Prescott Fire Department but the huge community around him and we're doing the best that we can to help him."
"It's not a good situation to not only be there, but to know that all of your buddies are gone," Wade said.
"He did exactly what he's supposed to do and the crew did exactly what they're supposed to do," he said. "There's nobody to blame. This is an accident."
The tragedy came at the start of the state's monsoon season, a weather phenomenon that brings lightning strikes, gusty winds, dust storms and sometimes rain to the state during the summer months.
Karen Takai, a fire information officer at Sandia Ranger district in New Mexico, said at a news conference today that the losses have been emotional for the firefighters who are still fighting the blaze but that they are determined to extinguish the fire for their fallen comrades.
"They were fighting the fire on the mountain. That was their charge. That was their job," Takai said. "To honor the firefighters, they're going to put this fire out."
A lightning strike Friday in Yarnell, about 90 miles northwest of Phoenix, started the wildfire amid triple-digit temperatures and low humidity.
The winds that helped fuel the fire were notably unpredictable and contributed to the rapidly shifting nature of the blaze. The early monsoon storms typically have plenty of lightning and wind, but often have little rain. Those ingredients make up a deadly combination in a state that is bone-dry. Seventy-five percent of Arizona is suffering from severe drought or worse.
"When those two collide, you get unexpected fire behavior and surprising fire behavior and explosive fire behavior," Takai said.
The Yarnell fire has burned through 8,400 acres and none of it is contained. There are 18 engines, eight support water tenders and a total of 500 personnel on the scene. An estimated 200 homes and other structures burned in Yarnell and the Yarnell Fire Department and Yavapai County will continue to assess the community today.
Air tankers continue to drop fire retardant on the flames, but experts say Sunday's tragedy won't keep them from sending men and women to the frontlines.
"It takes a firefighter on the ground digging a fire line that stops the advance of the fire," former U.S. Forest Service wildfire expert Jim Paxon said.
Today is expected to be another punishing day for firefighters with heavy hearts, still mourning the loss of their fallen brothers. A high of 115 degrees is expected.
Remembered as Loving Sons, Caring Fathers
The ages of the Granite Mountain Hotshot Crew ranged from 21 to 43, with 14 in their 20s. They were young men in the prime of their lives, like 21-year-old Kevin Woyjeck, whose father is a Los Angeles fire captain.
"He's a great kid," Los Angeles firefighter Keith Mora said. "I say kid, but he was a young man. He was working very hard."
Wade Parker, 22, was engaged to be married this fall. Sean Misner, 26, leaves behind a wife who is seven months pregnant.
Andrew Ashcraft, 29, leaves behind and wife and four children.
"Our oldest is struggling a lot," Ashcraft's wife, Juliann, said. "I want them to be like their dad. We have three boys and one girl. And he loved them and now it's my job for them to know how much he loved them.
"He's the best person I've ever met and he gave all for his job and it doesn't compare to what he gave his family. And they were all like that. They were heroes," she added.
Bill Warneke, 25, was 6 when he dressed up as a fireman. He later joined the Marines and then the Hotshots. He joined the Hotshots in April, Warneke's grandfather Jack told ABC News.
Chris MacKenzie, 30, was a Hotshot veteran, according to his mother, who never worried about his safety.
"Chris was very experienced and he had taken a lot of classes and he had done it for such a long time," Laurie Goralski said.
Mourners, Arizona Diamondbacks Pay Tribute
Sunday was the deadliest day for U.S. firefighters since 9/11, when 340 died in New York City. The Arizona Diamondbacks just happened to be in New York playing the Mets Monday night when both teams paid tribute to the hotshots.
A baseball jersey with the number 19 hung in each team's dugout with the name "Yarnell." During the four-game series, the Diamondbacks will wear black bands on the right arm of their jerseys to pay tribute to the fallen firefighters.
"We'll never replace what they've had to go through, but hopefully we can help them in some capacity," Diamondbacks manager Kirk Gibson said.
There was a moment of silence at ballparks across the majors.
More than 1,000 people turned out Monday to a Prescott gymnasium to honor the bravery and sacrifice of the firefighters.
ABC News' Sabina Ghebremedhin, Anthony Castellano and The Associated Press contributed to this report.