BOISE, Idaho (AP) — Officials are asking residents of about 60 homes in a small central Idaho town to voluntarily evacuate as fire crews battle a nearby wildfire.

The Boise County Sheriff's Office said Monday afternoon that residents living east of Alder Creek in Garden Valley should consider evacuating because of the danger posed by the Calder Fire. The Calder Fire is one of about 20 blazes sparked by lightning across the Boise National Forest during a storm Sunday night. Boise National Forest officials say most of the fires are still very small, but the dry forest conditions and hot weather are causing firefighters some concern.

The wildfires were all estimated at less than about 6 acres Monday afternoon, but they stretch across a swath of land nearly 40 miles long from Garden Valley to the South Fork of the Payette River.