FLORENCE - Humid weather and a growing force of firefighters kept the Mason Gulch fire at bay Tuesday, but the risk of a flare-up prevented a few thousand residents from returning to their homes. The lightning-sparked fire grew from 11,700 acres to 12,200 acres on its sixth day, a modest increase for a large wildland fire. The blaze was 40 percent contained. A Type I fire management team, the most advanced and heavily equipped available, took over Tuesday morning. “If all goes well,” said David Dallison, a fire behavior analyst with the new team, “I think we’ll be wrapped up within a week.” The prognosis could change, he and others cautioned. Wind-fed flames tearing across driedout stands of oak and pine could defy the most thoroughly analyzed predictions. Last weekend, dry lightning storms sent the fire spewing through miles of dense forest. The uncertainty kept Pueblo County from allowing about 5,000 evacuated residents in the Beulah area from going home Tuesday. Nine hundred homes are threatened there. Residents of Greenwood, a Wetmore neighborhood near the fire’s origin in Custer County, were allowed to go home Monday. Dallison, who analyzes weather, trees, terrain and other factors to anticipate the fire’s next move, expected another calm day today. At Florence High School, the command post for firefighters, dozens of tents were sprawled across the grass. About 830 people, 17 aircraft and 56 fire engines were working on the fire Tuesday as the cost rose to $2.6 million. After a nighttime shift and five days on the fire, Robert Finif of the Northwest Fire Protection District was going home to Fairplay. His crew members spent their time protecting ranches on the fire’s western edge. By the time they left, progress was evident. “(The fire) got to the line and fizzed out,” he said. Gordon Roetker, a Cañon City firefighter with the Tallassee Rural Fire Protection District, lazed on the lawn at noon Tuesday after working through the night monitoring hot spots and mopping up areas around the northern part of the burn zone. The fire was basically out in that area, Roetker said. Ironically, a wet winter contributed to the fire’s intensity. Heavy snow broke tree branches, which litter the forest floor and help form a ladder for flames to climb, said Dallison, the fire analyst. The moisture helped grasses grow taller before they dried out and became potential fire fuel.