Local fire officials have confirmed that 19 firefighters have died while battling the Yarnell Hill Fire in central Arizona.
The Prescott Fire Department confirmed to MyFoxPhoenix that 18 firefighters, all part of a crew called the Prescott Granite Mountain Hotshots, had passed away Sunday evening.
An official with the Yavapai County Sheriff's Office later confirmed to Fox News that the death toll had risen to 19.
Prescott Fire Chief Dan Fraijo said at a news conference late Sunday that 22 firefighters were injured, and 8 required hospitalization.
He described the fire, which started after a lightning strike Friday, as a fast-moving blaze fueled by hot, dry conditions. Temperatures reached into the triple digits across the state Sunday, with a similar forecast for the following day.
"This is as dark a day as I can remember," began a statement by Arizona Governor Jan Brewer.
"It may be days or longer before an investigation reveals how this tragedy occurred," the statement continued, "but the essence we already know in our hearts: fighting fires is dangerous work.
The risk is well-known to the brave men and women who don their gear and do battle against forest and flame.
"When a tragedy like this strikes, all we can do is offer our eternal gratitude to the fallen, and prayers for the families and friends left behind. God bless them all."
The National Fire Protection Association had previously listed the deadliest wildland fire involving firefighters as the 1994 Storm King Fire near Glenwood Springs, Colo., which killed 14 firefighters who were overtaken by a sudden explosion of flames.
U.S. wildfire disasters date back more than two centuries and include tragedies like the 1949 Mann Gulch fire near Helena, Mont., that killed 13, or the Rattlesnake blaze four years later that claimed 15 firefighters in Southern California.
State forestry spokesman Art Morrison told the Associated Press that an estimated 200 homes were also destroyed by the blaze, which fed on dry grass near the communities of Yarnell and Grand Isla.
The sheriff's office has notified residents in the Peeples Valley area and in the town of Yarnell to evacuate.
Earlier Sunday, the fire prompted the evacuation of at least 50 homes in the Buckhorn, Model Creek and Double A Bar Ranch areas about 85 miles northwest of Phoenix.
The wildfire also forced the closure of about 15 miles of state Route 89, the Arizona Department of Transportation announced. The department did not have an estimate of how long the closure would last but advised drivers to use U.S. 93 or Interstate 17 as alternate routes.
Fire information officer Mike Reichling said earlier Sunday that no homes had been lost in the fire northwest of the Yavapai County community of Yarnell.
Early estimates put the number of evacuated homes at 120, but the number was downgraded by officials closer to the fire.
Reichling says the blaze was within a mile of some homes but was burning away from them.
The Yarnell Hill Fire prompted evacuations in the Model Creek, Buckhorn and Double A Bar Ranch areas about 85 miles northwest of Phoenix. The blaze also was within 200 yards of the Model Creek School.
Crews cleared brush and did other work around the evacuated homes to help guard against the fire.
On Sunday afternoon, the Yavapai County Sheriff's Office called residents in the Peeples Valley area and in the town of Yarnell, telling them to evacuate.
Two hundred firefighters are now working at the fire, but an additional 130 firefighters and more water- and retardant-dropping helicopters and aircraft are on their way.
The Sheriff's Office said the Red Cross has opened a shelter at Yavapai College in Prescott.
In another Arizona fire, a 2-acre blaze that started at a motorcycle salvage yard and spread to a trailer park has destroyed five mobile homes in the Gila County community of Rye, located more than 130 miles east of Yarnell.
Gila County Health and Emergency Services Director Michael O'Driscoll said no one was injured in Rye.
The fire was ignited Saturday night at All Bikes Sales located off Highway 87. It spread to neighboring federal Forest Service land but was fully contained within 12 hours of its start.
The cause of the fire is under investigation.
The Red Cross says seven adults and two children were staying at a shelter set up for people who were evacuated.