A wildfire 60 miles away wrapped Denver in a pungent cloud of smoke for several hours and complicated the aerial offensive against the spreading mountain blaze, which has killed one person and destroyed more than 100 structures.
In southern New Mexico, a 56-square-mile fire threatening the village of Ruidoso damaged or destroyed at least 224 homes and cabins, and that number was expected to increase.
Workers found only heaps of burned metal and other debris on home sites hit hardest by the Little Bear fire.
"It's truly heartbreaking to see the damage done to this beautiful part of the country," New Mexico governor Susana Martinez said after touring the area.
With at least 19 large fires burning in nine US states, President Barack Obama called Colorado governor John Hickenlooper to assure him that the federal government stood ready to provide personnel, equipment and emergency grants for Colorado and other states battling fire.
Mr Obama also tried to reach Ms Martinez, but her office said poor reception in the fire zone kept the two from connecting.
The 68-square-mile High Park Fire in Colorado shrouded Denver, some 60 miles south, in a smoky haze.
The smoke temporarily grounded the air attack on the fire, but helicopters and tanker planes took to the skies by midday.
The wildfires in the drought-stricken West have tested federal resources.
US Forest Service chief Tom Tidwell announced late Monday the agency was contracting eight heavy air tankers to increase the ageing national fleet to 17.
In Colorado's Larimer County, authorities and family said Linda Steadman, 62, perished inside her mountain cabin.
Her home received two evacuation warnings that were not answered, and a firefighter tried to reach the cabin before fire overtook the site, Sheriff Justin Smith said.