It happened on northbound 99 near the Avenue 96 offramp just outside Pixley.
CHP officers say somehow a semi tractor and trailer ended up on its side.
Reports say the trailer was carrying tens of thousands of pounds of groceries.
Traffic is now moving in one of the lanes and many are exiting at Avenue 96.
No word on when traffic will be cleared along the 99.
If you are planning to use the highway, you might want to consider using an alternate route until the scene has been cleared.