Living in the Bay Area, it’s quite possible to become a fog aficionado, if you’ve come to accept the idea that being surrounded by a cloud has its own quiet and chilly charm.
With all the cold and moist days we’ve been having lately, it’s the perfect time to experience the winter’s tule fog, an entirely different variety of fog than the summertime’s ocean-borne type.
Named after the tule grass wetlands of the Central Valley, tule fog starts inland on cold wet nights. Cold air absorbs moisture from the damp earth and condenses into dense fog that hugs the ground so tight it can be quite dangerous. The Central Valley has notorious traffic snarls because of tule fog, which can reach a visibility of a foot at its worst. Because of air pressure differences, the tule fog tends to drift westward to sea, sometimes channeling through the Golden Gate in the reverse direction of summertime fog. Coastal inhabitants bask in sunshine while the sunny side of the bay is enveloped in gray.
In summer, fog forms from moist ocean air that is cooled by the frigid upwelling of currents. So, it seems, the Bay Area gets fog year round — just a different type from a different direction.
The official time frame for tule fog is November 1- March 1, so enjoy it while you can.
Photographer Marc Crumpler has been out capturing images of tule fog, and other wintertime fog and shares these photos from East Bay parks.
Help Bay Nature tell more stories about nature in the Bay Area
Make a tax deductible donation to Bay Nature today!
Most recent in Weather
Hot weather can be tough on our local wildlife, including wild bees. But you can help by making a safe "watering hole" for tiny pollinators.
Current climate change research suggests California’s weather could become even more variable than in the past, a “new normal” of drier dry periods punctuated by wetter winter storms.
Climate Change | Water | Weather