SAN DIEGO (CBS 8) - Local weather conditions forced classes in the Julian and Spencer Valley School District to be on a delayed start Tuesday morning.

If you plan on heading to the mountains, watch out for black ice and snowy conditions.    

The second of two El Nino-driven Pacific storms hit San Diego County Monday, bringing wintry weather, mountain snow, big waves at the beaches and widespread downpours.

About a foot of snow had fallen on Palomar Mountain by mid-morning, prompting authorities to require that tire chains be used in the area.

A winter storm warning for the mountains expired at 3 a.m. Tuesday.

Numerous snow showers developed Monday and continued into the early evening, decreasing Monday night into early Tuesday, according to the weather service.

The snow level dropped to about 4,000 feet Monday night. Up to 14 inches of snow could accumulate in altitudes of more than 5,500 feet, and up to 18 inches could fall in areas higher than 7,000 feet.