A SigAlert was issued in Vista at Gopher Canyon Road and East Vista Way after a motorhome collided head-on with a sedan, authorities said.
The crash between the small camper and blue Nissan Altima happened around 6:30 p.m.
At least one patient was trapped inside one of the vehicles, and emergency crews were working to extricate the patient, authorities said.
The small, 26-foot motorhome was towing jet skis and a dune buggy. It is unclear if any of those vehicles were also involved in the collision.
Officials issued a traffic alert at 7:10 p.m. and are working to assist those involved in the accident.
There is no word on potential injuries, if any, just yet.
Check back for updates.