Overturned big rig jams southbound 5 Freeway traffic in Burbank

An overturned big rig shut down several lanes of the southbound 5 Freeway during the busy morning commute in Burbank.

The wreck occurred around 5:30 a.m. near Burbank Boulevard. The big rig, which ended up partially on top of a K-rail, was leaking milk.

Traffic appeared to be squeezing through a single lane as emergency personnel worked to clear the scene.

Southbound traffic was backed up for miles.

The cause of the crash was not immediately known.