Fog flows, pure and simple. In the Bay Area we call it ‘Nature’s Air Conditioning’ and at the Golden Gate Bridge we announce its presence by activating the fog horns until visibility clears across the Shipping Channel below the bridge.
The fog comes
on little cat feet.
It sits looking
over harbor and city
on silent haunches
and then moves on.
—Carl Sandburg, Fog
July marks the traditional start of Fog Season, averaging 161 hours of fog horn operation for the month. The highest number of hours of fog horn operation was in July of 1979, when the horns ran for a total of 361 hours.
Small vessels that do not have radar still use the Bridge fog horns as guides when visibility in the Golden Gate Strait is low. Each horn has a different pitch and marine navigational charts give the frequency, or signature, of each fog horn. Vessel operators heading into the San Francisco Bay steer left of the south pier horn and right of the mid-span horn. Outbound vessels stay to the right of the mid-span horn.
Photo Notes: iPhone 4 camera, Camera+ app, edited in Snapseed.