A brush fire started just after 4 p.m. Monday near Interstate 15 and Deer Springs Road in unincorporated Escondido.
A SigAlert has been issued. Currently, only two lanes of southbound I-15 are open, and one lane of the northbound side is closed.
Thick smoke is blowing across a portion of the freeway, potentially making it difficult for drivers to see, according to the California Highway Patrol.
CHP and Cal Fire crews are on scene. Check back for updates on this developing story.
View Deer Springs Rd & Interstate 15 in a larger map