Officials have mapped a wildfire burning in the Bob Marshall Wilderness and now estimate that it has scorched 500 acres.

The fire ignited Thursday 24 miles southwest of Augusta, where smoke from the blaze could be seen. Lewis and Clark National Forest officials say the fire is believed to have started by lightning.

That smoke jumpers and a state helicopter were responding to the blaze.

Four aerial tankers dropped retardant on the fire Thursday.

On the Montana-Idaho line, the Chrandal Creek fire had burned 2.6 square miles by Friday morning. The fire was burning 42 miles south of Darby in the Bitterroot National Forest.

Fire officials say some residents in the Hughes Creek area have been contacted and issued an evacuation alert.