Dry thunderstorms laced with strong, erratic winds that shifted unexpectedly in the high heat of the Southwest likely created the perfect storm that trapped and killed 19 experienced firefighters in Yarnell, Ariz., officials say.
The wildfire that killed 18 of 20 members of the Granite Mountain Hotshot Crew Sunday in Yarnell 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. The 19th dead firefighter was from another group.
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," said Karen Takai, fire information officer at Sandia Ranger district in New Mexico.
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
Fourteen of the Granite Mountain Hotshot Crew were in their 20s, with ages ranging from 21 to 43. 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," L.A. 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' David Wright and The Associated Press contributed to this report.