More than 100 firefighters were working Tuesday to contain the Dry Creek fire, which had burned about six acres in rugged U.S. Forest Service land north of Highway 7 in rural Boulder County. The fire began Tuesday morning. By 3:30 p.m., crews had established a containment line and the blaze was 25% contained, according to the U.S. Forest Service’s Arapaho and Roosevelt National Forests office. Aircraft were dropping fire retardant around the fire’s perimeter as ground crews laid hose lines. Evacuation warnings were issued for Pine Valley and Riverside residents, people along the Dry Creek St. Vrain Trail and rural roads in the area. A warning means people should be ready to leave; officials had not issued evacuation orders as of Tuesday afternoon. Boulder County public information officer Vinnie Montez said one firefighter was injured but not seriously and was able to evacuate without assistance. “Fire crews are working really hard to get hose laid around the fire,” Montez said during an afternoon update. Children were evacuated from Balarat Outdoor Education summer camp, which is run by Denver Public Schools. Firefighters were staging equipment near South St. Vrain, east of Allenspark, and officials urged drivers in the area to use caution.