A 4‑acre grass fire broke out Thursday along the southbound 405 Freeway near the 105 interchange, backing up traffic as emergency crews worked along the roadway. Fire officials say forward progress had been stopped as of 6 p.m. Units surrounded the fire and were extinguishing hot spots, with no structures threatened and no evacuations ordered. Stream Los Angeles News for free, 24/7, wherever you are. WATCH HERE WATCH HERENo injuries have been reported and the cause of the fire remains under investigation as traffic continues to be impacted in the area.