Aphyllon [formerly Orobanche] fasciculata (clustered broomrape). I saw (and photographed) a amall patch of these on the roadside in May 2014. I wonder if this big patch is the same bunch, now greatly expanded?
2017AphyllonMorgan FireOrobanchaceaeOrobanchePFSF Bay Area
From Mt Diablo: The fourth April after the fire - April 23 2017