Nearly three weeks after the Alexander Mountain fire started west of Loveland, U.S. Forest Service officials have declared the wildfire to be 100% contained.

The fire, which started July 29 and is being investigated as human-caused, was completely contained Saturday, the Forest Service said on social media. 

At the peak, 625 personnel were on scene fighting the fire, which destroyed 51 structures and burned 9,668 acres in Larimer County north of the Big Thompson Canyon. The U.S. Forest Service has been in command of the fire scene after the Southwest Incident Management Team 1 returned control Aug. 9 when the fire was at 91% containment.

The fire destroyed 26 homes and damaged at least four others, according to a report by the Larimer County Assessor’s Office. Twenty-one outbuildings were also destroyed.

Firefighters will continue to monitor the burn area, which is mostly on U.S. Forest Service land, as the Burned Area Emergency Response team continues to search for areas at risk of mudslides or flash flooding in the future.

“The Forest (Service) wants to recognize both the hard work as well as the stress and difficulty of the past three weeks,” acting Arapaho and Roosevelt National Forests & Pawnee National Grassland Supervisor Jason Sieg said in a social post Saturday night. “There are members of the Cedar Park community who lost property and homes, and we will support them as best we can alongside our community partners and local agencies. We also want to thank the numerous agencies, partners, fire personnel and community members who stepped up to help in our joint coordination with Larimer County and Colorado Division of Fire Prevention and Control. This was a team effort.”

U.S. Forest Service wildland investigators are working with the Larimer County Sheriff’s Office to chase clues on who may have started the fire, even if it wasn’t intentional. They think the fire started between 10:30 a.m. and 11:15 a.m. July 29. Anyone with information about the start of the fire can call the Forest Service’s tip line at 303-275-5266. 

Alexander Mountain is one of three Front Range wildfires being investigated as human-caused and ignited in the last week of July. 

Arson investigators are still looking into the cause of the Quarry fire, which grew to nearly 580 acres in a highly-populated area of Jefferson County before firefighters got the perimeter fully under control Aug. 7. Federal investigators are also looking into the Stone Canyon fire that destroyed five structures and is linked to one death in Boulder County. It was fully contained Aug. 4 after burning 1,557 acres.

Forensic experts in Boulder County are still working to identify a person whose remains were found in the rubble of the Stone Canyon fire, but the condition of the remains is posing a challenge for investigators.

The remains were discovered in the aftermath of the Stone Canyon fire, which ignited July 30 north of Lyons, before it burned more than 1,500 acres. Five homes were destroyed and one person was killed.

The fire caused extreme changes in the skeletal remains, including dehydration, fragmentation, color alteration and loss of material, that make extracting DNA more complicated, the Boulder County coroner’s office said in a news release Wednesday. 

DNA samples are often the only reliable method for identification in such cases, the coroner’s office said. 

“The integrity of the bones is significantly compromised after a fire, making it extremely difficult to obtain usable DNA,” Boulder County Coroner Jeff Martin said in the release. “In addition, locating a living family member for comparative DNA analysis can further complicate and delay the process. We are dedicated to overcoming these challenges and are utilizing every available resource to assist in this identification effort.” 

The Boulder County Sheriff’s Office confirmed the body was found inside a burned property in the 2600 block of Eagle Ridge Road, but have released little additional information on the investigation. 

The investigation continues into what caused the fire. Federal investigators from the Bureau of Alcohol, Tobacco, Firearms and Explosives were looking into the fire alongside Boulder County authorities. 

While the cause of the fire is still unknown, the ATF’s involvement indicates authorities believe it was human-caused. 

The wildfire was one of three along the Front Range that forced thousands of people to evacuate their homes in the foothills north and west of Denver during the last week of July. Firefighters from around the state and county raced to control the flames that quickly spread amid extremely dry and hot conditions in Colorado.

Investigators have determined that the Alexander Mountain fire, which has burned nearly 10,000 acres in northern Colorado and destroyed 51 structures, was human-caused. 

The fire was sparked July 29 west of Loveland in Larimer County. As of Friday, it had burned 9,669 acres and was 91% contained.

The fire destroyed 26 homes and damaged at least four others, according to a report by the Larimer County Assessor. Twenty-one outbuildings were also destroyed.

U.S. Forest Service wildland investigators are working with the Larimer County Sheriff’s Office to chase clues on who may have started the fire, even if it wasn’t intentionally. 

Investigators are asking anyone with information about the start of the fire to call the Forest Service’s tip line at 303-275-5266. Photos, videos and typed statements can also be uploaded online. 

They are interested in information about anyone who was in the area immediately east and below the peak of Alexander Mountain, photos of the fire between 10:30 a.m. and 11:15 a.m. July 29 and information from anyone who spends time in the Alexander Mountain area.

Alexander Mountain was one of three Front Range wildfires that officials have determined were human-caused and ignited the last week of July, before rain brought much-needed relief to extremely dry conditions. 

Arson investigators are still looking into the cause of the Quarry fire, which grew to nearly 580 acres in a highly-populated area of Jefferson County before firefighters got the perimeter fully under control earlier this week. 

On Saturday, officials from the Larimer County Sheriff’s Office and the Forest Service made their way to where they believed the fire started. Sheriff John Feyen said it was a “hard hike to get in there,” and that’s when they started their forensic investigation. They know the origin of the fire and that it was human-caused, but have not released further information on the investigation. 

Federal investigators are also looking into the Stone Canyon fire that destroyed five structures and is linked to one death in Boulder County. 

The cause of the fire is still unknown, but the involvement of the Alcohol, Tobacco, Firearms and Explosives, alongside Boulder County officials, indicates that authorities suspect it was human-caused.

The Quarry fire that prompted hundreds of residents to be evacuated as flames crept dangerously close to homes in Jefferson County is now 100% contained, officials said Wednesday, about a week after a sheriff’s deputy found a fire burning in an open space and it quickly escalated. 

Arson investigators are still looking into the human-caused fire, which grew to nearly 580 acres before firefighters had the perimeter fully under control, the Jefferson County Sheriff’s Office said. 

The fire started around 9 p.m. July 30 in Deer Creek Canyon and when it was discovered it was burning on only about 100 square feet. But with dry fuels and low moisture, the fire grew to 100 acres within three hours. 

Officials say they know the origin of the fire and that it was human-caused, but have not released additional details on the investigation. 

Anytime you see a fire like that start at 9 p.m., “it makes you scratch your head a little bit,” Mark Techmeyer, a spokesman for the sheriff’s office, said the day after the fire started.

As of Tuesday morning, all evacuated residents were allowed to return to their homes.

Firefighters are making strides in containing the two wildfires still burning in the foothills as higher moisture levels and lower temperatures bring relief across the Front Range. 

Crews are focusing on smoldering interior areas of the Alexander Mountain fire near Loveland, but the fire isn’t expected to grow, fire managers said in a Tuesday morning update. The fire didn’t show any growth overnight and remains at 9,668 acres and is 83% contained, as of Tuesday afternoon. 

As evacuated residents start to return to their homes, officials urged them to be aware of the 536 firefighters and emergency personnel still in the area and to follow all forest and road closures. 

While rain brings much-needed moisture to the fire footprint, an increased chance of rain could bring flash flooding and debris flows to areas that are downhill and downstream from burned areas, the U.S. Forest Service warned. 

Light winds will increase across the fire area throughout the day and a light haze is expected until storms roll in. Nearby communities, including Eden Valley, along U.S. 34 to Idlewild and Drake, will see residual and overnight smoke, the forest service said.

Investigators continue to look into what caused both fires, but expect to give their final daily news conference on firefighting efforts at 4 p.m. 

In Jefferson County, the Quarry fire burning was estimated at 527 acres and 45% contained as of Tuesday morning.

As of 10 a.m., all evacuated residents were allowed to return home, the Jefferson County Sheriff’s Office said. All residents must have credentials issued at the evacuation center at Dakota Ridge High School at 13399 W. Coal Mine Ave. 

Only residents with access cards will be allowed in the area for the next two days as firefighters work on final clean up, the sheriff’s office said. General access will be allowed starting Thursday. 

All communities that were issued mandatory evacuation orders will be placed under pre-evacuation status, the sheriff’s office said.

The Stone Canyon fire that destroyed five structures and is linked to one death is 100% contained, leaving investigators to scour the blackened area near Lyons to figure out what caused the blaze. 

Federal investigators from the Bureau of Alcohol, Tobacco, Firearms and Explosives were looking into the fire alongside Boulder County authorities, the agency said on X. The federal law enforcement agency investigates acts of arson, as well as terrorism and illegal storage of explosives.

The cause of the fire is so far unknown, but the involvement of the ATF indicates authorities suspect it was human-caused.

Local authorities announced Sunday night after completing aerial surveys that the fire was fully contained and that all evacuations and road closures were lifted. It burned 1,557 acres and had not grown in the prior four days. 

“People are just so relieved and grateful,” said Hollie Rogin, mayor of Lyons. “Everyone is hoping to get a little sleep. Of course we are devastated about the loss of homes and the loss of life.”

Rogin and her husband, Patrick, evacuated their home in Lyons last Tuesday after receiving an alert via phone. She grabbed her passport and their two dogs, Pearl and Poncho, and dropped them off at Updog Daycare in Boulder. 

“We found what I think was the last hotel room in Longmont,” Rogin said. 

The mayor said she was touched by the small town’s generosity during the fire, including when the city put out a call for batteries and other donations for the fire crews, who had come from as far as Pennsylvania. Within three hours, there were three pickup trucks full of donated supplies, she said. 

“We really know how to come together when times get tough,” Rogin said. “We saw that during the flood. We saw that during the height of COVID.” 

“At one point we had 250 firefighters in our little tiny town of 2,200 people.” 

The mayor said she expects an extra-large turnout at Wednesday night’s regularly scheduled summer concert series, when people gather to hear music at Sandstone Park. People are filled with relief and gratitude and will want to celebrate, she said. 

“This fire is contained and we are so grateful,” she said, “but I am personally going to be on pins and needles until it snows. I would encourage everyone to have two takeaways — adhere to fire ban rules and be prepared. Have your go-bag ready.”

Meanwhile, fire crews continued to battle two other fires in the Front Range, including the 10,000-acre Alexander Mountain fire in Larimer County, which was 54% contained as of Sunday afternoon. They were also making progress on the Quarry fire, in Jefferson County. 

Rain fell around Denver on Sunday night, bringing some relief to firefighting operations and clearing smoke from the air.

The fires that started last week forced thousands of people from their homes and burned a combined 52 homes and outbuildings. 

In Jefferson County, authorities said the Quarry fire was human caused, but they are not sure yet whether it was accidental or intentional. 

Jefferson County authorities also said Monday afternoon that they were “so close” to allowing evacuated residents to return to their homes but did not want to give a timeline.

“We are very optimistic that we are well on our way to getting people back in their homes safely so they will not have to evacuate again,” said Karlyn Tilley, a spokesperson for the Jefferson County Sheriff’s Department. “We are very excited that this is going faster than we even thought it was going to.” 

Fire crews worked through the night on a controlled burn that began on the southwest side of the fire and then turned the corner heading north. They were using bulldozers and chainsaws to remove the fire’s fuel  “so that the fire has nothing to eat,” she said. “It’s blowing in the right direction and it’s burning the right things. We are very excited about that.” 

Sunday night’s rain was welcomed by firefighters, but they were hoping for a more soaking rain Monday night, which would speed up the process of allowing residents to return home, Tilley said. Fire crews have been working 24-7 and could use “help from Mother Nature,” she said.

“It’s steep. It’s grueling. It’s hot. They are staying overnight extra hours because they want to get the residents back into their homes.” 

Residents will be allowed to return 48 hours ahead of the people who want to hike on trails in the canyon or drive through the burned area, she said. “We just want to give them a moment to breathe,” Tilley said. 

The fire has burned 527 acres and is at 45% containment. “There will be firefighters throughout this area for weeks to come,” she said. “It is a long, arduous process to make sure there aren’t any flare-ups.”

While it was a very productive weekend for crews working three wildfires along the Front Range, there is still much work to do to get full containment on the Alexander Mountain and Quarry fires, officials said.

The biggest news from the weekend was the Stone Canyon fire, which started Tuesday morning north of Lyons, was completely contained as of Sunday evening. The Lyons Fire Protection agency is now in charge and mopping up the interior of the fire as the investigation into the cause continues.

The Quarry fire, which started Tuesday night in Jefferson County and is being investigated as arson, is 45% contained as of Monday evening and minor growth with the completion of a controlled burn.

Much the same in Larimer County as hundreds of firefighters continue to work on the Alexander Mountain fire, which started Tuesday morning. That fire is 74% contained after burning nearly 10,000 acres, officials said during a rainy news conference Monday afternoon.

The Larimer County sheriff said Saturday that investigators from his office and the U.S. Forest Service reached the remote area that morning where they think the fire started, but did not give more information into a potential cause. That was reiterated Monday afternoon.

Catch up: Read live updates from Wednesday, Thursday, Friday, Saturday and Sunday.

Alexander Mountain fire

Focus on hot spots as containment climbs

With a jump to 74% containment Monday afternoon, officials said the number of personnel fighting the fire will decrease. At one point there were more than 600 firefighters working the fire.

“With the great success we’ll see our numbers drop,” Carl Schwope with the Southwest  Incident Command Team said Monday afternoon during a rainy news conference. “That’s a lot of folks doing a lot of good work.”

Crews are zeroing in on hot spots inside the burn scar, with the help of aerial surveillance using infrared technology. 

“We’re going in to make sure there’s no more heat in there. So it’s kind of search and destroy for any kind of heat,” said Jayson Coil with the Incident Command Team. “Last night on the infrared (flyover) we asked them to turn it up until they could see deer, then back it down a notch so we can pick up every one of those little spots, and then they went in after those spots today.” 

There are still 929 homes inside the mandatory evacuation area, but that is expected to drop in the next few days.

— 4:25 p.m. Monday

More than 600 personnel remain on fire

The goal Monday for the 625 personnel working the fire west of Loveland is to continue to protect homes in the Cedar Park area and locate any remaining “hot pockets of fuel,” per the Monday morning update.

“As more containment is achieved, crews will turn their focus to locating areas holding heat in the interior of the fire and patrolling containment lines,” officials said Monday.

The fire has not grown in size the past few days as firefighters secured lines along Highway 34 in the Big Thompson Canyon and on the eastern edge.

—10:21 a.m. Monday

Quarry fire

Containment nears halfway mark

As firefighters continue to work on the interior of the wildfire and securing fire lines, officials said Monday evening the fire was 45% contained and had burned 527 acres.

That added acreage was in part due to about a 50-acre controlled burn, which has been ongoing the past few days, on the west side of the fire. 

— 5:30 p.m. Monday

Progress with controlled burn

Firefighters are nearly finished with a controlled burn on the west side that crews started over the weekend. That work will help with containment and means more evacuations could be lifted soon, said Jefferson County spokeswoman Karlyn Tilley. 

“The controlled burn we are doing right now is going absolutely great,” she said during a news conference Monday afternoon. “The weather is cooperating. Overnight it was absolutely wonderful. We were able to get so much of that extra fuel burned out, and we only had about 50 acres left this morning to burn. Once that is done we’ll have a much better chance of getting all of our residents back in their homes.” 

She said the rain overnight gave firefighters some relief but it did not do much to dampen the fire. More rain is in the forecast Monday night.

“If we get some good rains tonight, we’ll be even closer. … We’re hoping for a more substantial rain tonight,” Tilley said.

The fire remains at 472 acres burned and 35% contained, but those numbers are likely to increase after a flyover this afternoon, she said. There is no timeline on when evacuations will be lifted.

— 2:50 p.m. Monday

Drones continue to be problem

The plan Monday is for “increased burn operations today utilizing helicopters,” according to a morning update. Firefighters and local officials said they continue to have problems with drones and small fixed-wing planes over the area, which can cause air operations to stop for safety reasons. There has been a temporary flight restriction in the area since the fire started July 30, and investigators are looking into pilots breaching that order.

The investigation continues into the cause of the fire, and it is being investigated as arson, either started intentionally or unintentionally.

A news conference is scheduled for 2:30 p.m. Monday for the latest updates.

—10:26 a.m. Monday

Stone Canyon fire

All clear for residents to go home

All evacuations and road closures were lifted Sunday evening when the fire was considered 100% contained. The Lyons Fire Protection District now controls the operations and will be doing mop-up operations Monday, the agency said in an update Monday morning.

“There may still be smoke within the burn area as crews work to mop up any hot spots. Please only call 911 if flames are visible, or if smoke is coming from outside the burn area,” the districted posted on Facebook.

The cause of the fire, which started Tuesday morning, remains under investigation and the Bureau of Alcohol, Tobacco, Firearms and Explosives is one of the agencies helping with the investigation. 

—10:42 a.m. Monday

Crews battling three major wildfires on the Front Range celebrated fresh gains Sunday, paving the way for some evacuees to return home while racking up a near-doubling of containment of the Alexander Mountain fire. 

The nearly 10,000-acre Alexander Mountain fire was 54% contained as of Sunday afternoon, up from 32%, after crews gained an upper hand on the entire eastern flank and reported significant progress along the Highway 34 corridor. The Quarry fire was 35% contained as of Sunday afternoon, up from 20%. And the Stone Canyon fire was declared fully contained, up from 90% containment a day earlier. 

The advances came despite another day of sweltering heat in the 80s, challenging firefighters wearing hot protective gear and wielding heavy tools.

The weather forecast calls for rain and thunderstorms on Sunday evening and in days ahead,  offering a welcome break from the heat — and the potential for hazardous high winds and lightning. 

The change in the weather brought fresh risks to fire crews assigned to all three fires in northern Colorado, which have forced thousands of people from their homes, killed one person and burned at least 25 houses and many other outbuildings. 

“It’s very important that we watch the thunderstorms, because winds from those storms can be very dangerous,” said Kari Fleegel, a National Weather Service incident meteorologist assigned to the Quarry fire, in discussing the week’s forecast. 

A planned, 48-hour power outage was announced for parts of the Quarry fire to assist in operations. The outage is necessary as firefighters conduct controlled burns along a worrisome corner of the blaze in the afternoon and evening, in the hope of preventing the fire from spreading into an area of unburned fuels in steep, rugged terrain. 

Those crews were treated to a light rain Sunday afternoon, in a welcome morale boost.

“It was a nice refresher, but had no effect on the fire,” said Mark Techmeyer, a spokesperson for the Jefferson County Sheriff’s Office.

Even so, crews on the Quarry fire were upbeat after a weekend of positive news.

“We’re really happy where we are,” Techmeyer said. “Everything’s worked out in our favor, and we’re going to get this thing done.”

Alexander Mountain fire

Containment increases after “major successes” on fire lines

The fire is now 54% contained — up from 32% — after firefighters rack up “major successes,” including containing the entire eastern perimeter and making significant gains along the Highway 34 corridor, fire officials said in a statement.

No new growth was reported.

More than 500 personnel were fighting the blaze.

— 4:30 p.m. Sunday

Forecast brings chance of rain — and threat of high winds and lightning

Showers and thunderstorms are possible this afternoon and evening, offering a break from hot, dry weather, while also bringing fresh threats for fire crews. 

Some rain has already fallen in the Cedar Park area on the northwest side of the fire. 

The forecast for calls for similar chances of rain and thunderstorms in days ahead, particularly Wednesday and Thursday.

While rain can calm hungry fires, thunderstorms packing high winds can dry out fuels and fan flames, ramping up danger for firefighters. Crews must be ready to move to safety quickly when storms are in the forecast, Fleegel said. 

—4 p.m. Sunday

More residents cleared to return home

Fire officials on Sunday gave the “all clear” for residents to return to the following areas:

-East of County Road 27 from Highway 34 to Masonville
-Pinewood, Flatirons, Carter Reservoir area, including Pole Hill
-Glen Haven and the Dunraven Glade Retreat area

In addition, the following areas were downgraded to voluntary evacuation zones:

-County Road 43 from the Retreat to Drake
-East from the Little Dam Store including Green Ridge Glade Reservoir, Eden Valley, Bobcat Natural Area and Sylvan Dale

Residents may text LCEVAC to 888777 for updates. Visit www.nocoalert.org for a map of the updated areas.

—noon Sunday

Crews making “great progress” on containment lines

Crews focused on protecting homes along U.S. 34 and extinguishing hot spots near Cedar Park.

“Although the fire will not be as aggressive, spread is still possible,” Carl Schwope, incident commander for the Southwest Area Incident Management Team wrote. 

Gusty winds could cause the fire to spread in any direction. 

—8:30 a.m. Sunday

Stone Canyon fire

Stone Canyon fire is declared fully contained

Aerial surveys confirm the deadly fire is now 100% contained, after four days with zero fire growth, officials said.

The size estimate grew by a few acres based on a careful assessment of geographic information system data.

— 6:30 p.m. Sunday

No growth overnight, though smoke from hot spots is possible

Containment and acreage remain unchanged Sunday after a night of little fire activity.

Crews are mopping up in the fire’s interior, and smoke from periodic hot spots is possible, Boulder officials warned.

“Please only call 911 if you see flames or smoke outside of the fire perimeter,” an advisory said.

—9:24 a.m. Sunday

All roads open; evacuations lifted

All evacuations were lifted and all roads are open after crews gained significant control over the fire, officials said Saturday evening. 

The cause of the fire remains unknown

—8 a.m. Sunday

Quarry fire

Officials keep an eye on the weather while conducting controlled burns

Controlled burning was ongoing Sunday evening, and largely complete in areas underlying power lines. That could allow for power to come back on Monday in areas where it was turned off, Techmeyer said.

Fire commanders were optimistic about their progress even as they keep a wary eye on storm clouds.

“The thing we are most worried about is not the rain, but the shifting winds,” Techmeyer said. 

The day’s successes came thanks to 190 firefighters from nearly 20 agencies, along with 14 fire engines and one bulldozer.

Techmeyer had no updates on the arson investigation.

“We’re working it,” he said. “We want this person as bad as everyone.”

— 6 p.m. Sunday

Power outage planned to aid in firefighting efforts

Fire officials announced a two-day, planned power outage in parts of the fire area to assist in ongoing operations.

CORE Electric Cooperative will be shutting off power for approximately 48 hours from the intersection of Grizzly Drive and South Deer Creek Canyon Road west to South Mckinney Road, officials said. Everything south of that area for 3 miles will also be darkened.

Some homes in the Sampson neighborhood, which remains evacuated, will be also be affected.

—3:30 p.m. Sunday

Firefighters work to control fire in overgrown open space

The northwestern side of the fire remains a challenge for firefighters, Techmeyer said at a Sunday morning briefing. 

“Really no boots can go in because it is so steep,” he said. 

Saturday night firefighters targeted that remote area by setting controlled fires to burn fuels in thick, overgrown areas, until 1 a.m. when temperatures were lower and flames were easier to control, Techmeyer said.

Those efforts are seen as critical, because of concerns that fire will make a run through the area.

Tomorrow’s 48% chance of rain is generally good news for firefighters, but it could put a damper on controlled burns, he said. 

“It’s just a dance with Mother Nature,” he said. 

Techmeyer said he expects the containment to increase Sunday as firefighters make more progress on fire lines. 

Residents who have been cleared to return to their homes will need to show a driver’s license or some other proof of address to pick up badges at the evacuation center. They must present badges to enter closed areas and return to their houses.

“We’ve got to keep traffic to a minimum because we still have fire trucks and a ton of people working that area and they will be for quite some time,” Techmeyer said.

“This is not done. It’s not over. Stay in pre-evac mindset.”

Flames still remain about a quarter-mile from homes.

—8:25 a.m. Sunday

There is a cat in Jefferson County with eight lives left. And don’t be surprised if you see it show up on T-shirts as the symbol of resilience for those displaced by the Quarry fire.

Fire crews on Friday found a cat covered in red slurry inside the burn scar. Other than needing a bath, the cat is fine, Jefferson County Sheriff’s Office spokesman Mark Techmeyer said Saturday afternoon. 

“You have a cat that’s been out there for four or five days and was close enough to the fire to get hit by retardant,” he said. “I can’t imagine how scared it was trying to find its way.

“But that cat to me is the symbol of what we’ve been through here. That is survival, tenacity, and hanging in there and fighting.”

After being checked out at a local animal clinic the feline was reunited with its owners. Techmeyer didn’t know the cat’s name.

“If it doesn’t have a name, I hope they go with Slurry,” he said.

Crews working three wildfires burning along the Front Range will have another day of hot, dry weather to contend with Saturday as they try to gain greater containment on the fires that started earlier this week. 

The Alexander Mountain fire, which started Monday west of Loveland, has damaged or destroyed 49 structures, the Larimer County sheriff said Friday night. It has burned more than 9,500 acres. But by Saturday afternoon it was at 32% contained, up from 5% in the morning.

The greatest containment is on the Stone Canyon fire, which started Tuesday north of Lyons. Officials reported Saturday night they have 90% containment on the fire. One person died in the fire and five structures have been destroyed.

More resources are on the ground to fight the Quarry fire burning in Jefferson County. Officials say the fire was human-caused and an arson investigation is underway. The fire has burned 472 acres since starting Tuesday night in Jefferson County open space. It is 20% contained, officials said in a news conference Saturday.

The weather forecast for Saturday is concerning federal fire managers. Temperatures are expected to remain high, with the chance of thunderstorms that could bring erratic, gusty winds, though there is the possibility of rain in the Sunday outlook.

Forecast along the Front Range calls for near-record high temperatures this weekend, and the National Weather Service has issued a heat advisory for Sunday.

“Today, the weather is also concerning,” Jefferson County Sheriff Reggie Marinelli said Saturday morning. “If it were to drop rain for us, we’d be very appreciative of that. However, we all know in Colorado what comes with those small storms and that’s the lightning and the wind. So, we’re being very cautious about that.”

Catch up: Read live updates from Wednesday, Thursday and Friday.

Alexander Mountain fire

Containment up to 32%; investigation into cause starts

Officials announced a major jump in containment Saturday, with lines now built around 32% of the fire, up from 5% when the day started. The greatest gains are on the east side of the fire, near Masonville, and along the U.S. 34 corridor.

Larimer County Sheriff John Feyen said Saturday as containment improves they should be able to let some people back into their homes and “reduce the evacuation footprint tomorrow.”

Feyen also said that investigators from the sheriff’s office and the U.S. Forest Service were able to get to the area where they believe the fire started, but he did not have information on their findings.

“No determination or no final conclusion as to how it happened,” Feyen said. “It’s a hard hike to get in there, but they did get in there and that forensic work has started this morning.

Asked if the fire was human-caused, Feyen declined to speculate.

The fire burning to the north is running into the Cameron Peak fire scar from 2020, which is helpful to firefighters. That fire is the largest in state history and burned more than 208,000 acres and destroyed 469 structures. 

Federal fire managers said earlier this week that they would likely let the fire move about a mile into the Cameron Peak scar before beginning to turn the flames back.

More than 500 people are now working the fire.

— 4:31 p.m. Saturday

Cedar Park neighborhood big focus

The efforts Saturday for ground crews include boxing in the southwestern corner and the west side of the fire near the Cedar Park neighborhood. 

“Where we protected homes, now we’re going to get in there and work to try to create actual containment of the fire by connecting the dots,” Brandon Woodward, an operations chief with the management team, said in a morning update. 

Nearly 400 personnel are on the fire, which was at 5% contained as of Saturday morning.

— 12:51 p.m. Saturday

Nearly 50 structures damaged, destroyed

At least 25 homes were destroyed and four others were damaged as the Alexander Mountain fire moved through neighborhoods north of the town of Drake, the Larimer County Sheriff’s Office reported Friday night.

Not all of the property owners have been notified, Sheriff John Feyen said. All of the damage is in the neighborhood of Palisade Mountain and Snow Top drives and includes another 20 outbuildings that were destroyed. 

Investigators still are trying to reach people who have property on Cedar Creek Road, Spruce Mountain Drive, Green Ridge Road, Possum Court, Palisade Mountain Drive, Snow Top Drive and Bobcat Drive. Owners along those streets are asked to call 970-980-2800 to provide current contact information to the Office of Emergency Management.

Fire activity increased Friday on the northwestern edge of the fire and south of the neighborhoods where the homes were burned, federal fire managers said, causing more smoke in the afternoon. Crews protected an area near Cedar Springs Reservoir in the same neighborhood as aircraft dropped water and slurry on the western edge of the fire to slow its progress.

There are 398 firefighters working in rugged and steep areas above Big Thompson Canyon. Firelines on the fire’s eastern edge have held.

Smoke continued to be heavy in communities near the fire, including Glen Haven and neighborhoods north of Estes Park. Air quality warnings have been issued for most communities in Larimer and Boulder counties.

—7 a.m. Saturday

Stone Canyon fire

One neighborhood still under evacuation orders

Boulder County authorities opened all of Stone Canyon Drive to residents and others on Saturday, leaving only the Moss Rock neighborhood just to the east, off limits.

The area includes 11 homes and was described as “still hot.” The Office of Disaster Management said fire and utility crews were working in the area, preparing for the evacuation to lift.

In town Saturday morning there was little evidence of the fire that terrorized Lyons earlier in the week. Barbecue grills in LaVern M. Johnson Park, which includes tent camping sites, were covered and posted with Boulder County’s countywide ban on open flames outdoors.

— 4:45 p.m. Saturday

Firefighters circling flames

More evacuation notices have been lifted as firefighters made major headway Friday in containing the fire. It is now more than halfway contained as ground crews circle the blaze. 

The fire remains active and smoke will still be seen through the weekend, officials said.

—7:15 a.m. Saturday

Quarry fire

Fire lines being drawn as containment doubles

Firefighters made big strides Saturday in containing the fire, which hasn’t grown much in size the past few days. The fire is now 20% contained, up from 10% Saturday morning.

“That is a big step up from where we’ve been,” Jefferson County Sheriff’s Office spokesman Mark Techmeyer said during a news conference Saturday afternoon. “We’ve made a lot of progress, folks.”

A big part of getting the lines in rugged terrain has been the work of two Hotshot crews, which are about 20 people each and trained to work in dangerous areas. 

Techmeyer said residents are “gonna see a lot of smoke” Sunday as firefighters set intentional fires on the west side — in what he dubbed “no man’s land” — where the terrain is the most difficult.

— 4:45 p.m. Saturday

Rattlesnakes, bears in mix

A part of the fire is burning in an area known as Rattlesnake Gulch, and the Jefferson County sheriff said Saturday morning firefighters have encountered rattlesnakes and as well as inquisitive bruins.

“They came across rattlesnakes yesterday as well as bears that are very curious as to what they are doing,” Sheriff Reggie Marinelli said. “Those are some safety issues for firefighters. But the number one safety issue is the heat.”

Containment on the fire is expected to increase today as crews secure and connect fire lines.

“I expect that (10% containment) number to jump. I anticipate a much bigger jump today,” Jefferson County spokesman Mark Techmeyer said Saturday morning. 

He said more smoke will be visible Saturday because of the work crews are doing on the west side in open space.

“It’s to be expected,” he said. “We don’t want anyone to panic and think things are getting out of control. It is intentional, and you’ll see that today.”

— 8:20 a.m. Saturday

Work on hand lines helping with containment

Firefighters on Friday were “very aggressively” digging hand lines that have connected to fire breaks cleared by bulldozers, Jefferson County Sheriff’s Office spokeswoman Karlyn Tilley said Friday afternoon. That, combined with continued air support, has increased the containment and kept the fire from spreading.

No structures have been damaged, but two firefighters sprained their ankles while working on the steep terrain Friday.

Investigators are bringing in the state’s K9 fire investigator as they look for what started the fire, which was human caused, Tilley said.

—7:43 a.m. Saturday