Tahoe National Forest officials believe a person started the 15,738-acre American Fire, but what’s not known is if it was deliberately set.

Forest Supervisor Tom Quinn at a public meeting on Tuesday said a late model pickup was in the area and two men were hitchhiking out of the area. The investigation is ongoing.

The blaze is 63 percent contained, with full containment expected on Sept. 1.

On the extreme south end, firefighters will begin building a very steep hand line today, which descends to the river. The west side of the fire was relatively inactive. Mop-up is occurring in this area, which involves checking the interior of the fire.

The fire is burning in steep terrain about 10 miles from the town of Foresthill. Smoke continues to mar the air in the Placerville, Truckee and Reno areas.

 — Lake Tahoe News staff report