All lanes of southbound U.S. Highway 101 in San Francisco are blocked tonight because of a multi-vehicle crash there, according to the California Highway Patrol. The crash was reported shortly before 8:30 p.m. near the Cesar Chavez Street offramp.

The exact number of involved vehicles has not been determined, however initial reports suggest as many as six or seven vehicles may have crashed there, including a big rig.

An overturned Toyota may have a pregnant woman trapped inside, so first responders are trying to be extra cautious, according to the CHP. The lanes are expected to be blocked for at least 30 minutes.