(CNN) -- Arizona firefighters battling a deadly blaze are getting big help from the U.S. military: four specially equipped C-130 firefighting aircraft, CNN has learned from the Defense Department.
The planes will help fire crews attack the zero-contained Yarnell Hill blaze, an 8,400-acre conflagration that killed 19 firefighters Sunday. About 400 ground personnel and 100 incident management staff are working to control the fire, shadowed by the loss of their comrades.
"You have to acknowledge it," Karen Takai, a spokeswoman for the firefighting effort, told reporters Tuesday morning. "You can't push it behind in your head, but acknowledge it, and then they get their head back in the game. They have to focus very hard on the ground, or we'll be in that same circumstance again."
The fire has scorched about 13 square miles of the mountains outside Prescott, 80 miles northwest of Phoenix. Late Monday afternoon, the Yavapai County Sheriff's Office advised residents in the communities of Peeples Valley and Yarnell to evacuate their dwellings. An estimated 200 homes and other structures have burned in Yarnell.
The blaze didn't spread overnight, but firefighters are faced with another day of temperatures near 100 degrees and winds that can blow embers into new patches of woodland and mesquite grass, Takai said.
"That mesquite is extremely oily, and once that starts, an ember gets into those extremely dry fuels, that fire is going to rip," she said. "It's very difficult to control at that degree, especially with the winds that we're having out here."
Forecasters are predicting winds of between 8 and 13 mph, with gusts up to 21 mph. The National Weather Service projects a high temperature of 97 degrees for the area Tuesday afternoon.
Though firefighters got a break with higher humidity and brief showers in the morning, "The winds are just drying out that fuel right after the rain is hitting the ground," Takai said. "It's a pattern that is very difficult to work with."
The C-130 crews now joining the fight will have their work cut out for them in battling what is now considered the deadliest fire in state history.
Equipped with the Modular Airborne Fire Fighting System, or MAFFS, the planes, loaded with water or fire retardant, can drop 3,000 gallons in less than five seconds. The retardant covers an area one-quarter of a mile long and 60 feet wide, and the aircraft can land, reload and be airborne again in under 20 minutes.
The planes are from Colorado, where crews had been working on fires for the last several days. But they are now considered more vital for Arizona. The military deployment is coming at the request of civilian firefighting authorities asking for additional support.
A Defense Department official confirmed the details to CNN but declined to be identified because an announcement has not yet been made.
CNN's Barbara Starr contributed to this report.
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