april 12, 2017, redwood city, california, usa - warning gas pipeline marker up in the hills, on a cloudy sky background, south san

america area background bay bilingual blue california city clouds cloudy colorful contrast county creek danger dangerous edgewood editorial english focus francisco gas green hill industrial marker metal nature nobody north only orange outdoors park pipeline plate posted red redwood san selective sign signage silicon sky spanish states sunny symbol united use valley vegetation visible warning water white