By Keith Coffman
COLORADO SPRINGS, Colo. (Reuters) - Cooler temperatures and lighter winds helped firefighters on Thursday in the battle against Colorado's Waldo Canyon fire, which has destroyed hundreds of homes and forced more than 35,000 people to flee.
Thursday marked the first day in five days when a so-called red flag warning - indicating conditions that could increase wildfire activity - was not being posted in the Colorado Springs area, authorities said.
Despite the weather relief, the Waldo Canyon blaze remained devastating and only 5 percent contained, officials said. Exceptional high temperatures and strong winds have fueled the blaze, which started on Saturday.
It has burned 18,500 acres near Colorado Springs, the state's second-largest city, and the U.S. Air Force Academy.
"There was nothing left in some areas, burned out foundations that were smoldering. It looked like a nuclear weapon had been dropped. It's as close to hell as I could imagine," said Colorado Springs Mayor Steve Bach, who toured the heavily damaged Mountain Shadows subdivision.
Authorities have not released an official count of the number of homes destroyed in the Waldo Canyon fire but said the figure was in the "hundreds."
Colorado wildfires have killed four people this year in what the governor called "the worst fire season" in state history. No injuries from the Waldo Canyon Fire have been reported.
"Yesterday was a good day, and firefighters have made progress," incident commander Rich Harvey said at a news briefing on Thursday. "Now we're going to go after it aggressively."
More than 1,200 firefighters, supported by heavy air tankers and helicopters, are assigned to the blaze, Harvey said.
Temperatures were predicted to be five to seven degrees cooler than the average over the past week, and winds were expected to be only about 11 miles an hour (18 kilometers per hour), authorities said.
President Barack Obama planned to visit the city on Friday to meet with firefighters and tour the ravaged areas. More than 35,000 people have been ordered to evacuate.
The Waldo Fire was one of about a dozen blazing across Colorado on Thursday. The High Park fire, which burned 257 homes west of Fort Collins and north of Denver making it the state's most destructive fire in terms of property lost, was reported 75 percent contained on Thursday.
For the first time in five days, no red-flag warning was issued around the area of the 87,284-acre (35,322-hectare) High Park fire as well. Some evacuation orders were lifted, and some residents were allowed to return to their homes.
Near Boulder, the Flagstaff fire burned within 1.5 miles of the university city's southern edge.
The 230-acre (93-hectare) fire was 30 percent contained and "remains a threat to Boulder," said incident commander Rocky Opliger.
North of Grand Junction, near the Utah border about 240 miles (386 miles) west of Denver, a lightning strike sparked a blaze that grew to an estimated 700 acres. Authorities said it was burning in sagebrush and pinyon juniper in an area populated largely by wild horses.
Near Durango, in southwestern Colorado, firefighters were fighting a blaze 3.5 miles west of town.
Colorado accounts for eight of 35 large, active wildfires being fought across the country. Most were in the western states of Colorado, Montana, Utah, Wyoming, South Dakota, New Mexico, Nevada, Arizona and California, according to the National Interagency Fire Center in Boise, Idaho.
(Additional reporting by Ellen Miller,; Writing by Joe O'Leary; Editing by Ellen Wulfhorst and Vicki Allen)