The northernmost stretch of SR 39, from Snow Springs north of Azusa to SR 2 at Islip Saddle, has been closed to public vehicle traffic since 1978 due to a massive mud and rockslide. While the road is passable to emergency vehicles for the entire closed length, sections near reoccurring rock slides have become narrow dirt roads which are not suitable for passenger vehicles. According to Caltrans officials, it will take three years to complete the repairs.
