The destructiveness of the High Park Fire burning 15 miles west of Fort Collins surpassed the Fourmile Canyon wildfire, which destroyed 169 homes west of Boulder in September 2010.
More than 1,630 personnel worked on the fire Saturday, officials said in a late-night news release. That was an increase of more than 100 firefighters from a day earlier.
The lightning-caused blaze, which is believed to have killed a 62-year-old woman whose body was found in her cabin, was 45 percent contained, Cpl. Julie Berney of the Larimer County sheriff's office said Sunday. The fire's incident commander said full containment could be two to four weeks away.
Fire information officer Brett Haberstick said crews have made progress in containing a 200-acre spot fire that erupted Thursday afternoon north of the Cache La Poudre River, a critical line of defense against northward growth.
"Two 20-person hotshot crews worked throughout the day to secure lines around the perimeter of this spot fire," the officials said in a release.
Firefighters have extinguished other incursions north of the river, but the most recent one appeared to be more serious.
National Weather Service meteorologist Kyle Fredin said some rain was expected in the fire zone Saturday evening, but it will not be enough to put the fire out.
"We need a rain that will really last all day," he said. "But it's better than dry wind at this point."
Crews faced difficult conditions Sunday with wind gusts expected to hit 50 mph along ridge tops and in Poudre Canyon and temperatures in the 90-degree range.
The fire was reported June 9 and has since raced through large swaths of private and U.S. Forest Service land. It was 45 percent contained late Saturday.
Agriculture Secretary Tom Vilsack, who oversees the Forest Service, met with fire managers in Fort Collins on Saturday and said "fighting this fire is going to require us to be aggressive, persistent and also patient.
"We're going to continue to work to make our forests more resilient. We're going to continue to ensure that adequate resources are provided for fighting fires and we are going to continue to make sure that we encourage appropriate stewardship of our forests," he said.
Vilsack praised Congress for allowing the government to contract additional aircraft - particularly heavy tankers - to fight wildfires across the West. But he called on lawmakers for budget certainty to help plan for future fires.
Vilsack is scheduled to hold a news conference with U.S. Forest Service Chief Tom Tidwell in Albuquerque on Sunday.
Meanwhile in New Mexico, questions were being raised about whether bureaucratic red tape prevented firefighters from saving more homes affected by the Little Bear Fire after federal officials released transcripts of the firefighters' response.
Congressman Steve Pearce said Friday in an interview with KOB-TV (http://bit.ly/Mga1yx) that he believed federal officials could have done more after lightning sparked the fire outside the resort town of Ruidoso on June 4. Days later, high winds sent embers more than a mile from the blaze's end, causing the inferno to grow.
But officials released transcripts of the response on the Lincoln National Forest website that suggested firefighters were attacking the blaze as soon as it was a quarter of an acre.
The fire has destroyed 242 homes and commercial structures. It had burned 59 square miles and was 60 percent contained as of Saturday night.
Parts of the area received up to three-quarters of an inch of rain Saturday, aiding the firefight but causing flash flood warnings as a result of burned over forest. Lincoln County Emergency Services ordered an evacuation for residents in low-lying areas and around creeks or streams, but they were allowed to return home in the evening.
In Arizona, a blaze in the Tonto National Forest that doubled in size to 3,100 acres. Officials said Saturday night that the fire was 15 percent contained and firefighters continued to battle unseasonably dry fuels, high temperatures and low humidity.
On Friday, a crew member broke his leg fighting the blaze, which was burning in a remote, mountainous area about 70 miles northeast of Phoenix.
Associated Press writer Russell Contreras in Albuquerque contributed to this report.