YARNELL, Ariz. -- As the windblown blaze suddenly swept toward them, an elite crew of firefighters desperately rushed to break out their emergency shelters and take cover on the ground under the foil-lined fabric.
By the time the flames had passed, 19 men lay dead in the nation's biggest loss of firefighters in a wildfire in 80 years, including John Percin, Jr.,24, a 2007 graduate of West Linn High School.
"John was a brave and courageous man who never hesitated to put others before himself," Percin's family said Monday evening. "He was loved by many, and he will always be remembered.
"He is an inspiration to us all. Our thoughts and prayers go out to all of his fallen brothers and their families," Percin's family said.
His close friend since high school, 22-year-old Nick Havely, 22, was a close friend with Percin since high school.
"He was very energetic and outgoing," Havely told KGW. "He had a positive attitude about everything. He loves the outdoors so that's why it didn't surprise me when he told me he wanted to be a firefighter."
The tragedy Sunday evening all but wiped out the 20-member Granite Mountain Hotshots, a unit based in the small town of Prescott.
Fire Chief Dan Fraijo said as the last of the bodies were retrieved from the mountain. Only one member survived, and that was because he was moving the unit's truck at the time, authorities said.
The deaths plunged the town into mourning, and Arizona's governor called it "as dark a day I can remember" and ordered flags flown at half-staff.
"We are heartbroken about what happened," President Barack Obama said while on a visit to Africa. He predicted the tragedy will force government leaders to answer broader questions about how they handle increasingly destructive and deadly wildfires.
The windblown, lightning-sparked fire -- which had exploded to about 13 square miles by Monday morning -- also destroyed about 50 homes and threatened 250 others in and around Yarnell, a town of 700 people in the mountains about 85 miles northwest of Phoenix, the Yavapai County Sheriff's Department said.
Residents huddled in shelters and restaurants, watching their homes burn on TV as flames lit up the night sky in the forest above the town.
It was unclear exactly how the firefighters became trapped. Southwest incident team leader Clay Templin said the crew and its commanders were following safety protocols, but it appears the fire's erratic nature simply overwhelmed them.
Brian Klimowski, meteorologist in charge of the National Weather Service's Flagstaff office, said there was a sudden increase and shift in wind around the time of the tragedy. It's not known how powerful the winds were, but they were enough to cause the fire to grow in size from 200 acres to about 2,000 in a matter of hours Sunday.
The hotshot team had spent recent weeks fighting fires in New Mexico and Prescott before being called to Yarnell, entering the smoky wilderness over the weekend with backpacks, chainsaws and other heavy gear to remove brush and trees as a heat wave across the Southwest sent temperatures into the triple digits.
As a last-ditch effort at survival, members are trained to dig into the ground and cover themselves with a tent-like shelter made of fire-resistant material, Fraijo said.
"It's an extreme measure that's taken under the absolute worst conditions," Fraijo said.
Arizona Forestry Division spokesman Mike Reichling said all 19 victims had deployed their shelters.
The flames apparently enveloped the fire shelters. Autopsies were scheduled to determine how the firefighters died.
Hotshot crews go through specialized training and are sent in to battle the nation's fiercest wildfires. Sometimes they hike for miles into the wilderness with heavy gear to build lines of protection between people and fires. They remove anything that might burn in the direction of homes and cities.
More than 200 firefighters and support personnel were assigned to the wildfire as of Monday morning. They included 18 hotshot crews from around the country. Such crews typically have about 20 members each. The number of hotshot crews assigned to the fire is expected to at least double, Reichling said.
The U.S. has 110 hotshot crews, according to the U.S. Forest Service website.
Arizona is in the midst of a historic drought that has left large parts of the state highly flammable.
"Until we get a significant showing of the monsoons, it's show time and it's dangerous, really dangerous," incident commander Roy Hall said.
Jacques Billeaud reported from Phoenix. John Marshall reported from Yarnell. Associated Press writers Brian Skoloff in Yarnell and Martin Di Caro in Washington also contributed to this report.