Officials still don’t know what sparked the fire that burned about 1.5 acres near Chautauqua Park in Boulder on Saturday.
Wildland firefighters and Open Space and Mountain Parks rangers returned to the scene of the fire, which was first reported near Bluebell Canyon, Sunday and Monday to monitor the area and conduct an investigation, according to a Thursday afternoon release. Investigators have ruled out weather, powerline and foul play as potential causes.
The Bluebell trail and area closures are set to remain in effect through the weekend, so rangers and firefighters can continue monitoring burned areas. Trails are expected to reopen on Tuesday.
The fire, which was first reported around 12:45 p.m. Saturday, was considered fully contained by 6:30 p.m., according to the release.
More than 100 firefighters from multiple agencies responded to the fire, along with a Colorado Division of Fire Prevention and Control helicopter that made seven bucket drops — each containing 560 gallons of water — on the fire, according to the release.
Park rangers and firefighters evacuated hundreds of hikers from nearby trails.
No injuries were reported, and no structures were impacted.