BILLINGS, Mont. (AP) — Authorities are reporting progress on a wildfire threatening rural houses east of Roundup as fire crews dig in ahead of heat and wind that forecasters say could fan multiple blazes across the state.

Delphia Fire spokesman Pat Mckelvey said Monday that the lightning-caused fire between Roundup and Musselshell is 60 percent contained after growing to almost 55 square miles. Mckelvey says about 15 to 20 outbuildings have been destroyed, but no houses.

Claudia Rapkoch with NorthWestern Energy says the company is restoring power to the last of several hundred customers affected by a burned transmission line.

National Weather Service forecasters say hot weather will set in Monday and Tuesday, when dry thunderstorms could spark new fires.

Meanwhile, fires in neighboring Idaho have sent smoke pouring into western Montana.