On the first day of 2026, a remote mountain trail in northern Colorado became the scene of a rare and tragic encounter between humans and wildlife. Authorities confirmed that an adult woman was found dead on the Crosier Mountain Trail, just south of Glen Haven and roughly seven miles northeast of Estes Park, after what is being investigated as the first fatal mountain lion attack in Colorado in more than a quarter-century. The incident has sent shockwaves through the outdoor-loving communities of Larimer County and reignited public debate about safety and coexistence with the region’s iconic predators.
According to Colorado Parks and Wildlife (CPW) spokesperson Kara Van Hoose, the suspected attack unfolded around 12:15 p.m. on January 1, 2026. Two hikers, one of whom was a physician, stumbled upon a mountain lion lying partially over the body of a woman along a remote stretch of the Crosier Mountain Trail, which cuts through national forest land. As reported by The Coloradoan, the hikers were about 100 yards away when they spotted the big cat. They immediately began throwing rocks to scare the animal away, a tactic recommended by wildlife experts in such encounters.
“It was acting protectively over the person when the two men saw it,” Van Hoose told the press, as cited by The Coloradoan. Once the mountain lion retreated, the physician rushed to the woman’s side but, heartbreakingly, could not find a pulse. The victim’s identity and official cause of death are pending release by the Larimer County Coroner’s Office. Authorities believe the woman had been hiking alone at the time of the attack.
The emergency call triggered a swift and extensive response from local agencies, including the Glen Haven Area Volunteer Fire Department, Larimer County Sheriff’s Office, Estes Park Police, and CPW. The search for the mountain lion or lions involved quickly escalated, with officers aided by helicopters, houndsmen with tracking dogs, and even a CPW biologist who happened to be conducting aerial deer surveys in the area.
Wildlife officers located one mountain lion still near the scene. After being shot by officers, the animal initially fled but was later tracked down and euthanized. A second mountain lion was found nearby and also euthanized, in accordance with CPW policy that mandates euthanizing any wildlife suspected of attacking a person. As Van Hoose explained, “Agency policy calls for euthanizing wildlife involved in human attacks.” Necropsies—animal autopsies—will be performed on both animals to determine if either or both were involved in the attack. These tests will also check for abnormalities and neurological diseases such as rabies or avian influenza, and pathologists will look for the presence of human DNA.
As of January 2, 2026, a search for a third mountain lion reportedly seen in the area was still underway, and trails in the vicinity remained closed to ensure public safety. Local authorities have also closed several trailheads until further notice, as reported by CPR News and KUNC.
This harrowing event is particularly notable for its rarity. Fatal mountain lion attacks in Colorado are exceedingly uncommon. According to CPW, this would be only the fourth fatal attack since records began, and the first since 1999, when three-year-old Jaryd Atadero was killed while hiking with his family in Roosevelt National Forest. Since 1990, there have been 28 recorded mountain lion attacks on humans in the state, but only three have previously resulted in death.
Mountain lions, also known as cougars or pumas, are formidable predators. Adults can weigh up to 130 pounds and stretch more than six feet in length. Colorado is home to an estimated 3,800 to 4,400 mountain lions, making it prime habitat for these big cats. The animals are classified as a big game species and can be legally hunted—a policy that was upheld in 2024 when voters rejected Proposition 127, a ballot initiative to ban mountain lion hunting, by a 55% to 45% margin.
CPW and wildlife experts note that mountain lion sightings are common in the forested and rugged terrain around Glen Haven and Estes Park, especially in winter. As deer and elk descend to lower elevations in search of food, mountain lions often follow, raising the odds of human-cat encounters. “This is a very common time of year to take mountain lion sightings and reports and especially in Larimer County, where this is very good mountain lion habitat,” Van Hoose told The Associated Press.
While the Crosier Mountain Trail is beloved by hikers for its rocky climbs and secluded beauty, its remoteness also means that wildlife encounters can be unpredictable and, in rare cases, dangerous. The area is also home to bears and moose, further underscoring the need for caution. “Because mountain lion are really common in this area, we do expect to have conflicts with regular things like sightings or encounters with dogs,” Van Hoose told reporters.
CPW has renewed its safety advisories for anyone venturing into Colorado’s backcountry. Hikers are urged to travel in groups, keep pets leashed, and keep children close. If a mountain lion is spotted, experts recommend making noise, raising objects overhead to appear larger, and backing away slowly—never running. And if attacked, the best advice is to fight back. These guidelines, as reported by CPR News, have proven effective in past encounters, including a now-famous 2019 incident in which a trail runner fought off and killed a young mountain lion with his bare hands near Lory State Park.
The investigation into the Glen Haven fatality is ongoing. The necropsy results from the euthanized mountain lions will be crucial in confirming the cause of death and determining whether the animals had underlying health issues that contributed to their behavior. Until then, the community is left grappling with the sobering reminder that even the most familiar trails can hold unpredictable dangers.
As the region mourns and officials work to piece together exactly what happened, the tragedy on Crosier Mountain Trail has sparked renewed conversation about the delicate balance between outdoor recreation and wildlife conservation in Colorado’s wild places. For now, the message from authorities is clear: respect the wilderness, stay alert, and always be prepared for the unexpected.
