YARNELL, Ariz. (AP) — A sudden windstorm turned an Arizona forest fire into an out-of-control inferno that trapped and killed 19 firefighters, nearly all of them members of an elite crew of "hotshots," authorities said Monday. It was the nation's biggest loss of firefighters in a wildfire in 80 years.

The flames swept over the victims Sunday evening as they took cover in their foil-lined emergency shelters.

"This is as dark a day as I can remember," Gov. Jan Brewer said in a statement. "It may be days or longer before an investigation reveals how this tragedy occurred, but the essence we already know in our hearts: Fighting fires is dangerous work."

The windblown, lightning-sparked fire — which had exploded fourfold to about 13 square miles by Monday morning — also destroyed dozens of homes and sent hundreds fleeing from Yarnell, a town of 700 people about 85 miles northwest of Phoenix.

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.

View gallery."Toby Schultz lays flowers at the gate of the Granite …
Toby Schultz lays flowers at the gate of the Granite Mountain Hot Shot Crew fire station, Monday, Ju …
The fire killed 18 members of a hotshot crew based in nearby Prescott, plus a firefighter who was not part of the unit, Arizona Forestry Division spokesman Mike Reichling said.

One member of the hotshot crew survived because he was moving the unit's truck when the flames roared over the men, Reichling said.

It was unclear exactly how the crew 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.

The 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.

The disaster all but wiped out the Prescott hotshot crew, leaving the city's fire department reeling.