A mandatory evacuation is in force Monday for Oak Glen, about 90 minutes east of Los Angeles. The community has many apple orchards in rolling hills below the San Bernardino Mountains.
Forest Service spokeswoman Norma Bailey says the 900-acre blaze began Sunday afternoon and is burning out of control through oak and conifer woodlands.
There's only light wind but humidity is low. The high temperature is expected to top 90 degrees.
Another 2,400-acre blaze that began Thursday near Hemet is 95 percent contained.
Meanwhile, a 134-square-mile blaze continues to threaten 12,000 homes north of Los Angeles.