Extrapolating this vid to San Fransisco's roughly 7 mile diameter,the first rock the size of a school bus going 20,000mph would instantly destroy 2/3's of San Francisco.
The second rock-three football fields would destroy all the bay area and people in Livermore would see their clothing ignite from the heat and as far out as Modesto first degree burns for everybody out for a walk.
The third rock- as you might think of a rock over a mile in diameter- would take out most the states buildings, clothing ignite from San Francisco to Santa Barbara. First degree burns nearly border to border 745miles to Cal's about 800 mile length.
And I didn't even include the Bay's little Tsunami from the Earthquake it makes or the liquefaction of bay fill on buildings- and people.
It really would be a crappy,crappy, day on the bay.