Despite desperate efforts and training, an elite squad of firefighters died Sunday in the midst of a deadly wildfire near Yarnell, Arizona. Unpredictable winds contributed to a rapidly shifting blaze.

Trapped by flames after winds shifted, 19 highly trained firefighters -- known as the “Hotshot” crew -- unsuccessfully deployed heat resistant tarps in last-ditch attempt to survive.

Among the firefighters killed, the majority in their twenties, were a father-to-be and sons who followed in their fathers into firefighting.

“Something is wrong, because that doesn't happen,” Laurie MacKenzie, mother of one of the firefighters, said. “They know what they're doing.”

The Yarnell fire is still out of control. As of Monday afternoon, 400 firefighters and support personnel were deployed to fight the wildfire. That number includes members of 18 Hotshot crews from around the U.S., the elite forest fire fighting units assigned to tough blazes.

The governor of Arizona, Jan Brewer has signed a declaration of emergency to make additional state resources available to crews battling an out-of-control wildfire that has claimed the lives of 19 firefighters.

"This is as dark a day as I can remember," 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 wildfire has destroyed hundreds of homes in Yarnell, a small town approximately 135 kilometres northwest of Phoenix.

"Through our steadfast dedication (we will) do whatever is necessary to get this fire under control before it causes even more heartache," Brewer said at a press conference Monday afternoon.

The fire, ignited by lightning, spread over 2,000 acres in blistering temperatures and forced residents to flee Sunday.

By Monday, officials estimated the wildfire has so far scorched 8,374 acres of land, based on aerial photos.

A community in mourning

The 19 firefighters were part of a 20-member Hotshot crew based in Prescott, which is located approximately 48 kilometres northeast of Yarnell.

Prescott Fire Chief Dan Fraijo released the names of the firefighters at press conference on Monday. He described the team as a “very young crew, very professional.”

Cari Gerchick, a spokesperson for Maricopa County, said the firefighters’ bodies have arrived at a medical examiner’s office in Phoenix where autopsies will be performed. Gerchick said the bodies were accompanied by an honour guard. “People were lining the street wanting to pay their respects,” she told CTV News Channel on Monday. “Everybody is overwhelmed, shocked and saddened.”

Mary Rasmussen of the Southwest area incident management team, said officials are planning a “very considerable memorial service” for the 19 firefighters.

“The unimaginable events that unfolded yesterday afternoon…have left us all in a state of shock and disbelief,” Rasmussen said Monday afternoon, adding that residents should expect a number of “spontaneous” memorial services in days to come.

At Prescott fire station where the elite firefighting crew was based, a makeshift memorial including flower bouquets and American flags, has been set up.

Prescott resident Keith Gustafson visited the memorial and placed 19 water bottles in the shape of a heart. "When I heard about this, it just hit me hard," he said. "It hit me like a ton of bricks."

Lone survivor was moving truck

According to the Arizona State Forestry Division, the lone survivor of the elite Hotshot crew was able to escape because he was moving a firefighting truck at the time the blaze overtook the team.

Southwest incident team leader Clay Templin said the firefighting crew was following safety protocols but it appears the wind-whipped fire simply overwhelmed them.

Sunday's tragedy marked the most firefighters killed in one incident in the U.S. since Sept. 11, 2001, when 343 firefighters were killed.

According to the U.S. National Fire Protection Association, the last wildland fire to kill more firefighters was in 1933 in the Griffith Park fire of Los Angeles. Twenty nine people were killed.

Hotshot crews are often deployed to wildfire zones where they build lines of protection between residents and fires.

Under extreme conditions, crew members dig into the ground and cover themselves with fire-resistant material as a survival tactic.

Reichling told the Arizona Republic that 19 fire shelters were deployed, and some firefighters were found inside them, while others were outside the shelters.

U.S. President Barack Obama called the firefighters heroes and said that their deaths are a reminder of the danger emergency personnel workers put themselves in every day while on the job.

"We are heartbroken about what happened," said Obama, who spoke from Africa on Monday.

He said his administration is preparing to help Arizona probe how the 19 deaths happened, saying the incident will likely force officials to answer questions about how they handle destructive wildfires.

With files from The Associated Press