LARIMER COUNTY — The High Park fire is already the most destructive wildfire in recorded Colorado history, but federal fire officials worry that even more homes could be lost to its flames over the next few weeks.

The fire, sparked by lightning June 9, has charred more than 85 square miles west of Fort Collins and destroyed at least 181 homes, Larimer County Sheriff’s executive officer Nick Christensen said Saturday.

“There has been a great community effort in response to this fire,” he said. “The loss we are dealing with will also be a community effort.”

The blaze is 45 percent contained, but weather conditions are expected to worsen today and Monday, and on the very active western flank, the fire will be allowed to burn until it reaches the natural fire line, Pingree Park Road 3 to 4 miles west, incident commander Bill Hahnenberg said.

Most of the territory between the fire’s current perimeter and the road is U.S. Forest Service land, but a handful of homes are in the fire’s path. Crews will use a “point protection” technique to shield the homes.

As the fire approaches, crews will do everything from building fire lines and removing fuels to setting up sprinkler systems around the homes, Hahnenberg said.

He said fighting the fire is a long-term project requiring “persistence and patience.”

“Our goal is to diminish the threat and to return the community to as close to normal as possible, as soon as possible,” he said.

The 181-home tally does not include outbuildings, Christensen said. And the count could climb as structure assessment teams continue to work through the 710 homes within the fire’s bounds.

Saturday’s estimate surpasses the 169 homes lost in the Fourmile Canyon fire in 2010 and the 133 homes destroyed in the Hayman fire in 2002.

The largest number of homes lost in the High Park fire were in the Rist Canyon area. Fifty-one homes were lost in the Davis Ranch area, 40 homes were destroyed in Whale Rock, 21 homes in Stratton Park and 17 homes in Poudre Canyon. Most of the homes were lost in the first few days of the fire, Christensen said.

The 55,050-acre fire is now the third-largest recorded in Colorado history. In 2002, Hayman burned 137,760 acres, and Missionary Ridge burned an estimated 71,739 acres.

About 1,600 firefighters are battling the blaze from the ground and air. Fifteen planes and 14 helicopters aided crews throughout the day.

Crews made significant progress on the 200-acre spot fire that jumped the Poudre Canyon on Thursday evening, prompting the evacuation of the Glacier View subdivision. It will probably be days before residents are allowed back into the subdivision.

Evacuation orders were lifted for several areas, including Santanka Trail and Cloudy Pass.

About 70 percent of the fire is on private land, and the rest is on federal land.

Crews made some progress Saturday but will be battling the fire under tough conditions. A red flag warning has been issued forecasting winds to 50 mph on ridgelines and in Poudre Canyon, and temperatures in the 90s. Crews have been sent to the northern edge of the fire to attempt to hold the line.

Crews have securedthe eastern flank of the fire, but total containment will probably take three to four weeks.

“If it takes time, we’ll make sure we have the necessary resources. But we may need some help from Mother Nature,” U.S. Agriculture Secretary Tom Vilsack said after he and Gov. John Hickenlooper and U.S. Sens. Mark Udall and Michael Bennet toured the fire.

Vilsack said there are about 24,000 wildfires burning across the country, compared with the 33,000 wildfires burning this time last year.

Next week, crews will assess areas where flash floods could become a concern, as well.

“This is something we’ve been through before,” Hickenlooper said. “We know how to handle it.”

During an afternoon briefing, Hickenlooper held up a photo of the tree that ignited the fire after being struck by lightning.

The governor asked for the photo and others after some residents, during a citizens meeting last week, expressed skepticism about the fire’s cause.