The 68-square-mile High Park Fire in Colorado shrouded downtown Denver, some 60 miles south, in a smoky haze early Tuesday. The smoke temporarily grounded the air attack on the fire, but helicopters and tanker planes took to the skies by midday. The fire was 10 percent contained Tuesday.

Larimer County authorities allowed some residents to return home but issued 25 more evacuation notices near the west side of the fire because of limited escape routes. Among those affected by the new evacuations were up to 100 people at a camp, plus Colorado State University's mountain campus at Pingree Park, Sheriff Justin Smith said.

The wildfires in the drought-stricken West have tested federal resources.

U.S. Forest Service Chief Tom Tidwell announced late Monday the agency was contracting eight heavy air tankers to increase the aging national fleet to 17.

Still, Colo. U.S. Sen. Michael Bennet urged President Barack Obama to sign a bill that would allow the Forest Service to buy as many as seven large air tankers outright. The U.S. House and Senate passed the bill last week.