Big rig jackknifes on southbound I-5.

Just after 12:00 a.m. Monday, a big rig traveling southbound on the I-5 jackknifed, causing two lanes to be closed.

The accident occurred near the Calgrove Blvd exit in Santa Clarita and the resulting lane closure was in effect for several hours.

By the time the peak morning commute rolled around the accident had been cleared up, although residual slowing and the rainy weather made the overall morning a slow one for motorists.