Firefighters took advantage of a lull in searing heat and shifting winds in Wyoming and Montana on Thursday to attack wildfires that have charred thousands of acres and forced dozens of residents to flee their homes.

Temperatures in the mid-80s, higher humidity and calm winds aided crews battling the 95-square-mile Oil Creek fire just northwest of Newcastle, a town of about 3,500 near northeast Wyoming's Black Hills. About 25 families were evacuated from Newcastle's outskirts. The fire was 40 percent contained.

In southeast Wyoming, heavy air power, including four large air tankers, helped increase containment of the 16-square-mile Squirrel Creek fire to 51 percent. The tankers included two military C130s from a fleet that was reduced to seven Monday when one crashed in South Dakota's Black Hills.

"We really knocked it for a change, instead of us getting whacked," said Larry Helmerick, spokesman at the fire. Authorities planned to allow more people to return to dozens of evacuated summer cabins near the Colorado line in Medicine Bow National Forest.