Traffic on southbound Highway 99 is flowing following a deadly big rig crash early Monday morning.

According the California Highway Patrol, a semi-truck veered off the road and crashed into a pole justs after 2:30 a.m. Because of the weight of the trailer, the cab of the truck caught fire. 

The driver of the truck was killed in the crash. 

The truck was hauling a Challenge Butter trailer. 23ABC contacted Challenge Butter for comment, but has not received a response. 

Cleanup is ongoing. It's not known when the scene will be cleared.