Firefighters got some help from cold Thursday morning temperatures in their successful effort to extinguish a wildfire burning south of Bancroft. The 20-acre fire in the Fish Creek Summit area of Caribou County was declared to be out at about 11 a.m. Thursday, authorities said. Thursday morning temperatures in the 20s and 30s were a major reason that firefighters were able to extinguish the blaze, according to Caribou County emergency management officials. The wildfire was reported by a passing motorist around 3:30 p.m. Wednesday along Highway 30 on Fish Creek Summit near Lund Road, authorities said. The fire burned away from the highway and spread into the adjacent hilly terrain. Firefighters from the Caribou County and Bancroft fire departments and the Bureau of Land Management and Forest Service responded to the fire.