King Tides, the term for the especially high tides that occur a couple of times each winter due to an alignment of the sun and moon's gravity with the tilt of the earth, hit the Bay Area this week Monday through Thursday, peaking on New Year's Day. The high tide Wednesday morning at 10:40 a.m. will be 7 feet 1 inch above sea level, likely causing some flooding in low-lying areas. Luckily, our calm weather conditions mean that the tides won't be exacerbated by any storm swells.
The term King Tide appears to originate in Australia and New Zealand and refers to the highest of tides that typically follow an semi-annual pattern, with the most notable tides happening during summer (January) on Australia's eastern coast, and in winter in California.
The tides serve as visual alarms, as CBS reports, for those hoping to raise awareness of the potential impacts of rising sea levels. The California King Tides Initiative is one of those groups, encouraging people to upload photos to their Flickr group showing flooded roads, beaches, infrastructure, and wetlands during the season of King Tides. The idea is to give visual evidence of what the permanent affects of rising seas will look like in coastal areas.
Last December, Bay Area residents documented flooding on the Embarcadero, in Mill Valley, and along roadways in Sausalito, as you can see from the Chron. Also at risk of flooding: Much of SFO, though perhaps not this season.
Another set of King Tides are due to hit at the end of January, from the 29th to the 31st.