LOS ANGELES (CBS) — Most of this week’s rough weather has already passed through Southern California, but a winter storm warning will remain in effect through noon Tuesday.

Schools within the Rim of the World Unified School District in the San Bernardino mountains will be closed Tuesday. Schools near the Grapevine in Frazier Park will start an hour later.

The California Highway Patrol has been monitoring the Grapevine, which has remained open despite rain, snow and the possibility of ice on the ground.

Officers say that so far, they have not felt the need for closures or escorts.

A 15-vehicle pile up caused major delays on the southbound 5 Freeway through the Newhall Pass Monday night. Roughly 50 firefighters responded to the wreck, which was likely caused by rain.