U.S. Forest Service and Riverside County firefighters responded to the fire, which was spreading at a moderate rate and jumped State Route 74 in a northeasterly direction.
According to the CHP, one structure had been surrounded by the flames, though it was unclear what the structure was or if it might have been occupied.
State Route 74 was shut down in both directions between Palowet and Ribbonwood drives and the public was asked to avoid the area.
The public is advised to avoid the area.