BOULDER, Colo. – Weary firefighters hoped the worst was over from a wildfire that destroyed nearly 170 homes in the Rocky Mountains foothills, but crews monitored were monitoring hot spots early Friday amid concerns that erratic winds could fan the flames and send them into Boulder.
Fearing further devastation, city officials had urged roughly 9,000 residents Thursday afternoon to prepare to evacuate at a moment's notice because of conditions that were ripe for fire — low humidity and strong winds. But as night fell, federal officials downplayed the risk to the university city of 100,000, even as gusts surpassed 40 mph.
"I'm not aware of any real threat to the city of Boulder right now," said Jim Thomas, head of the national team managing the fire effort.
Crews contained 45 percent of the 10-square-mile fire, though the line wasn't continuous. Thomas declined to speculate when it would be fully contained.
The blaze, dubbed the Fourmile Canyon fire, erupted Monday and quickly left smoking rubble where mountain neighborhoods, filled with million-dollar homes and scenic mountain cabins, once stood. Slopes of charred trees created landscapes resembling a barren winter with gray ash instead of snow.
Still, no more homes were lost to the fire Thursday. Thomas said there were no major signs of crowning, when hungry flames race along the crowns of trees or shrubbery.
Westerly winds of 25 mph with higher gusts forecast for Friday could complicate the efforts of 700 firefighters plus support personnel and air tanker crews. Heavy air tankers have trouble accurately dropping their loads of dull red retardant when winds surpass 35 mph, Thomas said.
Parts of central and northern Colorado and southern Wyoming remained under a red flag warning Friday, meaning conditions were ripe for fire. And in an abundance of caution, Thomas refused to rule out further trouble west of Boulder.
"There's always that risk with a major fire," he said. "We've seen a fire move eight miles in a day."
The cause of one of the fire that destroyed more homes than any other blaze in Colorado history remained under investigation. Authorities were looking at whether a vehicle crashed into a propane tank and set it off.
About 3,500 people have been out of their homes since Monday, many frustrated by a lack of lack of information about what was happening behind fire lines. Some got around roadblocks by hiking and biking in. A limited number stayed.
Lee McCormack made it to his house Thursday but was stopped at a roadblock on a second attempt.
"It's shut down. It doesn't matter how much you plead," McCormack. "I gave the cop a Power Bar and he still wouldn't let me up there."
The city of Boulder told west-side residents to prepare to leave if the fire moved into town, setting off a scramble by some. From tony mansions to the north to a college sprawl west of the University of Colorado to the south, some residents watered lawns or packed cars with possessions. Others assembled on a smoky mountain overlook after dark, waiting to see if the distant fire glow seen earlier in the week would reappear. It didn't.
Caitlin Kolibas, 22, a college senior who lives in the University Hill neighborhood, said her parents in New Jersey were "trying to get me a little more concerned." But the university held classes as usual.
Boulder resident Lisa Carmichael loaded her pickup with a precious keepsake: Her grandfather's rocking chair.
"I lived through the Malibu fire, where the fire jumped over the Pacific Coast Highway and burned houses on the sand," Carmichael said. "So I know that with this wind, if the fire department says to take it seriously, you should take it seriously."
The loss of homes surpassed that of the 2002 Hayman fire in southern Colorado, which destroyed 133 homes and 466 outbuildings.
Nationwide, about 2.6 million acres have burned this summer, about 50 percent less than the 10-year average, according to the National Interagency Fire Center in Boise, Idaho.
Associated Press writers Ivan Moreno and Ben Neary contributed to this report.