Firefighters prepared for another day of scorching temperatures and low humidity after calmer winds helped them battle a 970-acre wildfire burning in rugged terrain south of the flyfishing resort town of Lake George.

By nightfall on Monday, firefighters struck a cautiously optimistic tone that the Springer blaze would avoid about 150 evacuated houses in Park County.

“It’s calmed down but I don’t want this to lull anyone into complacency,” said Gregg Goodland, a spokesman for the U.S. Forest Service.

Firefighters established a few fire lines around the Springer fire, which was reported Sunday morning a couple miles north of Elevenmile Reservoir. The blaze would have to jump the South Platte River to reach the nearest homes, which remained a mile away Monday.

Still, the blaze remained uncontained despite the work of three helicopters,  two twin-engine tankers and 320 firefighters on the ground.

As a battle plan was executed Monday, fire officials began investigating rumors of how the fire began Sunday morning.

An explosion is being investigated as a possible cause of the blaze, said Park County Sheriff Fred Wegener. But sheriff’s office and Forest Service officials cautioned that the investigation is ongoing. Those with tips on blaze were asked to call (719) 836-4384.

Goodland said investigators are also looking into whether lightning on Saturday night could be to blame.

The manager at the Indian Paint Brush Ranch, who did not want her name used, said investigators visited the ranch just before 11 a.m. Monday.

The manager told The Gazette that she and 10 others were horseback riding Sunday when they heard gunshots and an explosion, then saw flames rise from some brush. The group immediately rode back to the ranch stables and called 911, she said. The manager said a few of the riders reported seeing a truck with two men leaving the area just after the flames ignited.

The blaze is third fire to hit Park County in a little more than a week. Elsewhere in the tinder-dry forests west and south of Pikes Peak, more small fires ignited Monday that kept other crews busy.

A spot fire near the Elevenmile Reservoir dam scorched a tenth of an acre, while three and a half acres burned just outside the Aspen Valley subdivision near Divide. Both were quickly doused, in part by crews already in the area fighting the Springer fire.

The number of firefighters battling the blaze grew throughout the day as more firefighters arrived from across Colorado and other states.

The reported size of the blaze also doubled Monday but much of the growth was due to more accurate mapping.

“It’s not a rapidly advancing fire, and we’d like to keep it that way,” Goodland said.

Fears of more dry weather in the forecast kept the owners of about 150 houses in Park County from returning home, while residents of two subdivisions in west Teller County were told to be ready to flee at a moment’s notice.

About 380 people — mostly children — at the Sanborn Western Camps in Florissant also evacuated to a high school in Colorado Springs. The popular summer camp for children spans about 6,000 acres in Teller and Park counties.

By midday, 138 horses were brought to the Teller County Fairgrounds arena. Most were from youth camps south of Florissant, including the High Trails camp run by Sanborn Western Camps.

Fire officials said on Tuesday they will continue trying to cut lines around the fire. Their biggest goal is to keep the fire from crossing the South Platte River, which would put hundreds of homes in danger.

The forces fighting the fire could grow Tuesday. Another 80 firefighters could join the battle.

Locals still think Springer will grow.

“It’s six weeks since we have had (rain),” said John Magoon, who has a cabin near the fire. “It’s green but its dry as a bone.”

Magoon said the blaze could easily claim his summer home of 23 years.

“If it burns, it burns,” he said. “We’re resigned to it. But it would be awfully sad.”