From the air, Martinez pointed to the terrain as being "impossible" in some areas.

"It seems daunting to us because it's now 190,000 acres," she told reporters. "It's going to keep going up. Be prepared for that."

More than 1,200 firefighters are at the massive blaze near the Arizona border. It has has destroyed a dozen cabins and eight outbuildings, fire information officer Iris Estes said.

Experts say persistent drought, climate change and shifts in land use and firefighting strategies mean other western states likely will see similar giant fires this season.

"We've been in a long drought cycle for the last 20 years, and conditions now are great for these type of fires," said Steve Pyne, author of "Tending Fire: Coping with America's Wildland Fires" and a life science professor at Arizona State University. "Everything is in line."

Agencies in New Mexico, Colorado, Arizona are bracing for the worst.