Several cars were involved in a collision on the 101 freeway Sunday afternoon just north of Seacliff, creating a large traffic jam.

California Highway Patrol logs showed the accident occurred in the southbound lanes at about 12:55 p.m. and involved four or five vehicles. The extent of injuries was unknown but CHP officers said at least one person appeared to have sustained a severe leg injury.

Details of how the accident occurred were not immediately available with a CHP dispatcher noting the crash is under investigation. The Ventura County Sheriff’s Office confirmed a helicopter was sent to the scene.

This story could be updated.