The following school districts were closed today due to the inclement weather: Mountain Empire Unified School District, Warner Unified School District, Spencer Valley School District, Julian Union School District and Julian Union High School District.

A blanket of snow has taken over parts of the San Diego region Tuesday.

The storm was active Tuesday morning, bringing with it widespread rain during the morning commute. A Winter Storm Warning is said to continue until 10 p.m. Tuesday night.

The California Highway Patrol warned drivers that chains are required on SR-78, mile marker 51 to 64; and SR-79, mile marker 0 to 20. Interstate 8 is open to all traffic as of 9 a.m., the CHP said.

Today's weather also forced the closure of several county roads:

-- In Otay Mesa: La Media Rd. at Airway Rd. closed due to flooding

-- In Alpine: Alpine Blvd., between West Willows to East Willows

-- In Spring Valley: Quarry Rd. closed between SR-125 to Lakeview due to flooding

Due to today's rainfall, the county's Department of Environmental Health issued a "general advisory" for San Diego's coastal waters.

Officials said: "Swimmers, surfers, and other ocean users are warned that levels of bacteria can rise significantly in ocean and bay waters, especially near storm drains, creeks, rivers, and lagoon outlets that discharge urban runoff. Urban runoff may contain large amounts of bacteria from a variety of sources such as animal waste, soil, and decomposing vegetation. While many coastal storm drains within San Diego County are permanently posted with white metal warning signs, additional temporary warning signs are not posted for General Advisories. Activities such as swimming, surfing and diving should be avoided in all coastal waters for 72 hours following rain. This includes all coastal beaches and all of Mission Bay and San Diego Bay. Elevated bacteria levels can persist after a rainstorm depending upon the intensity of the storm, volume of runoff and ocean and current conditions."

Colder temperatures are expected this evening into early Wednesday morning.

For the county's mountains, areas such as Julian, Descanso, Pine Valley and Warner Springs are expected to see up to 3 inches of snow. Mt. Laguna and Palomar Mountain could have snowfall of up to 8 inches. Travelers into the mountain areas are urged to have proper supplies -- such as tire chains, gas, water and food -- and prepare for visibility issues and treacherous road conditions.