Fresh crews and more aircraft joined the battle Tuesday against a wildfire that had forced 5,000 people to flee their homes, hoping improved weather would give them an edge.

The temperature had fallen, wind was light and humidity had risen in the area of 11,700-acre blaze in southern Colorado.

"It's a good day to fight fire," U.S. Forest Service (search) spokesman Dave Steinke said. "We want to take advantage of the weather today."

However, hotter and drier weather was expected to return Wednesday, he said.

No injuries had been reported and no homes were burned, but more than 1,000 houses, outbuildings and other structures were considered threatened by the fire in dry, steep terrain in the Wet Mountains about 150 miles south of Denver.

About 800 firefighters were on duty, aided by eight helicopters, seven air tanker airplanes and 58 fire trucks, Steinke said.

The fire, started last Wednesday by lightning, was only 30 percent contained Tuesday.

Firefighters shored up containment lines around the 50-home Greenwood subdivision, allowing about 100 people to go home Monday for the first time in two nights.

"They're going to see a little bit of a change of scenery," said Brian Scott, a fire information officer. "Firefighters had to cut off the lower limbs of trees, pull firewood from the homes, moved picnic tables and in some cases, they even cleaned the gutters."

Flames advanced to within about a few dozen yards of some homes, Scott said. Fire engine crews patrolled neighborhoods through the night.

The National Interagency Fire Center said 11 large fires were active Tuesday in Alaska, Arizona, Colorado, New Mexico, South Dakota and Texas. They had burned a total of 189,000 acres.