BOULDER, Colo. (KKTV) - A fire burning just west of Boulder is now 100 percent contained and investigators believe the blaze was sparked by a campfire in a homeless camp.
On Tuesday, the Boulder County Sheriff's Office said investigators pinpointed the origin of the fire to a hastily built fire ring on a city-owned open space park just outside city limits. No suspects have been identified. The fire cost about $725,000 to fight.
The residents of the 426 homes that remained evacuated were allowed back into their homes late Monday morning. Residents had been evacuated since early Sunday morning after flames were spotted near Sunshine Canyon. The canyon is near the city's downtown.
The citizen who noticed the flames called for help around 1:40 a.m. At that time, firefighters believed the fire was between 3-5 acres, but it soon grew to more than 60.
Commander Mike Wagner with the Boulder County Sheriff's Office said firefighters were able to keep the fire's growth to a minimum Sunday afternoon.
"It was a great day on the fire," he said. "[Firefighters] were really able to attack with a lot of air resources."
Wagner said Sunday evening that there were concerns about wind overnight, and that firefighters were going to remain on scene monitoring the blaze and attacking any hot spots and flareups.
The fire's size increased to 76 acres Monday, but it's unclear if the increase is because the fire grew or due to better mapping.
Wagner cautioned citizens and visitors to Boulder County to heed Monday's Red Flag warning.
"It is a little concerning because all local fire resources are committed to the Sunshine Fire right now. We really don't want to start another fire somewhere else in the county. So no shooting in the forest ... no open burning in the mountains, no open burning anywhere in the county."
Fire danger will be high along the Front Range until the area gets appreciable moisture.
No structures were lost or damaged.