Firefighters mopping up a 939,270-acre blaze in Yellowstone National Park Thursday braced for warmer weather that could heat things up as Army reinforcements eager to join the battle against a giant fire arrived in Montana.

"We have been leaning forward in the saddle," Col. Beau Bergeron said as 900 soldiers from Fort Lewis, Wash., arrived Wednesday to help fight a 247,000-acre blaze in west-central Montana.

Nine hundred more soldiers arrived Thursday, swelling the ranks of firefighters wrestling with the blaze to 3,000.

California's Gold Rush country in the Sierra Nevada mountains enjoyed a second day of favorable weather, bringing firefighters closer to containing a 52-square-mile timber and brush fire that destroyed 97 homes and 60 other buildings.