A blaze that erupted Tuesday along the city limits of Grand Terrace and Highgrove scorched about seven acres before crews began encircling it.
The non-injury “Blue Mountain Fire” was reported shortly before 4 p.m. in the area of East Main Street and Mount Vernon Avenue, on the north side of Box Springs Canyon, according to the Riverside County Fire Department.
The flames were initially concentrated in San Bernardino County but crossed into Riverside County within an hour, not immediately threatening any homes or businesses.
Eight Riverside County fire crews joined multiple units from San Bernardino County in working to establish tentative containment lines.
As of 5:15 p.m., the brusher was less than 10% contained.
There was no word on what might have triggered it.