SANTA ROSA (KRON) -- Severe weather is moving through Northern California knocking out power and causing damage from Santa Rosa to the South Bay.

In San Francisco, an amateur photographer posted video to YouTube showing what appears to be a water spout just offshore at Ocean Beach.  

The damage is worst in the North Bay.  In San Rafael, high winds knocked down power lines cutting off electrical service to hundreds of customers.

In San Mateo County, a tornado warning was issued Friday morning after radar spotted a storm capable of producing twisters between Half Moon Bay and Belmont.

In the Sierra, a huge pile-up has closed Interstate 80 heading to the Lake Tahoe area.

Stay tuned to KRON 4 and KRON4.com for the latest on this developing story.

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