(Prescott Hotshots take a break fighting an Oregon wildfire, 2008/Wikimedia)

The elite 20-person Prescott-based crew, called the Granite Mountain Headshots, was forced to use temporary shelters to try and survive, NPR News reported. The group was prepared to handle the most outrageous wildfires and are frequently deployed to the front lines due to their rigorous training.

Only one member survived because he was in a different location, authorities said.

The fire started Friday, about 85 miles northwest of Phoenix and spread from 2,000 acres to 6,000 as of late Sunday night, destroying about 200 homes. The cause of the fire is still unknown.

"It had to be a perfect storm in order for this to happen. Their situational awareness and their training was at such a high level that it's unimaginable that this has even happened," Prescott Fire Department spokesman Wade Ward told ABC's "Today" show.

Prescott Fire Chief Dan Fraijo said late on Sunday he did not know the circumstances that led to the 19 deaths, according to the Chicago Tribune.

"This is as dark a day as I can remember," Arizona 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 deaths of the 19 elite firefighters has paralyzed the Prescott community and a Facebook page honoring the 19 men garnered close to 200,000 likes as of Monday morning.

One Facebook user, Justin Tyler, said he knew the 19 men personally:

"I worked side by side with the Granite Mountain crew for two weeks last summer on the Wesley Fire in Idaho. During that two weeks I got to know these men in a way that only men can become acquainted on a fireline," Wrote Tyler. "Tired, dirty and pushing ourselves to the limits daily we still found time for pleasantries and humor. They were one of the strongest crews I have ever worked with and I will never forget them."

According to The  Arizona Republic, the Yarnell fire has caused the deadliest firefighting toll since 1933.

"Emotionally, we're devastated. We just lost 19 of some of the finest people you'll ever meet," Prescott fire chief Dan Fraijo says. "I mean, right now, we're in crisis."

Read more at NPR