SAN FRANCISCO (CBS SF) – A cold front hurled pulses of severe weather into the Bay Area Thursday, triggering hailstorms, lightning, thunder and intense downpours.

The stormy blast was a parting gift as one front moved out of the water-logged region to make way for another system that will be moving through the Bay Area overnight.

While some areas had clear skies, the San Francisco Peninsula took the brunt of the severe weather as cell after cell came onshore in Half Moon Bay and roared across the region beginning heavy downpours and lightning to cities including Palo Alto, Redwood City, Mountain View and Belmont.

In San Francisco, crews continued their efforts to secure a hillside near Glen Park where rockslide danger has forced the closure of heavily traveled O’Shaughnessey Blvd. The closure is creating increased traffic on Portola Avenue in Diamond Heights.

The San Francisco Department of Public Works is projecting that the closure will last into Friday evening.

In the East Bay, run-off from the storm has added to the flooding in Livermore’s Lake Del Valle. The regional park has been closed since last week’s storms.

Flooding at Lake Del Valle in Contra Costa County (CBS)

Flooding at Lake Del Valle in Contra Costa County (CBS)

The park’s main feature is a large reservoir that flooded and the waters receded only to receive more runoff from the latest bout of stormy weather.

East Bay Regional Park District spokeswoman Isa Polt-Jones said part of the Stream Trail in Oakland’s Redwood Regional Park was still closed due to downed trees and parts of the Iron Horse Regional Trail in Concord have been rendered off-limits because of localized flooding.

Over the last 24 hours, the latest storm dumped 3.16 inches in Santa Rosa, 3 inches in San Rafael, 2.17 inches in Kentfield, nearly an inch in San Francisco and 2.43 inches in Bern Lomond in the rain-soaked Santa Cruz Mountains.

Like Napa on Wednesday, Contra Costa County Administrator David Twa signed a proclamation of local emergency on Thursday in response to winter storm damage that has occurred in a variety of locations throughout the unincorporated parts of the County.

The emergency status enables the County to be eligible for disaster relief funding that might be available in the future.

The strong series of storms has led to widespread flooding, mudslides, sinkholes and damage to public buildings, flood control facilities and roadways throughout the county.

Most notably, Alhambra Valley Road remains closed between Bear Creek and Castro Ranch Roads.

A second less potent storm was expected to roll into the region late Thursday evening and a third more powerful storm was forecasted for arrival Saturday night into Sunday morning.