YARNELL, Ariz. -- As the windblown blaze suddenly swept toward them, an elite "Hotshots" crew of firefighters desperately rushed to break out their emergency shelters and take cover on the ground under the heat-resistant 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.
The tragedy Sunday evening all but wiped out the 20-member Granite Mountain Hotshots, based in the city of Prescott, Prescott Fire Chief Dan Fraijo said.
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 as 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.
The lightning-sparked fire 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. Officials said the crew was following safety protocols, and it appears the fire's erratic nature simply overwhelmed them.
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, chain saws and other heavy gear to remove brush and trees.
As a last-resort effort at survival, members are trained to dig into the ground and cover themselves with a one-man, bag-like shelter made of fire-resistant material, Fraijo said.
Arizona Forestry Division spokesman Mike Reichling said all 19 victims had deployed their shelters. Autopsies were scheduled to determine how the firefighters died.
Gov. Jan Brewer's voice caught several times as she addressed reporters and residents at Prescott High School. "I know that it is unbearable for many of you, but it also is unbearable for me. I know the pain that everyone is trying to overcome and deal with today," she said.