KING TIDES & SF BAY WALKING WATERHOODS TOUR

When: Saturday, January 13th, 2024

Time: 12:00PM - 1:30PM

Where: Albany Bulb, 1 Buchanan Street, Albany, CA, 94602

Join Wholly H2O and the SF Bay Chapter of the Sierra Club to learn about king tides and their impact on the Bay Area ecosystem. As the climate crisis continues, king tides in the Bay Area are becoming increasingly dramatic, demonstrating the extremities of flooding along the coastline and into the flats. We'll also be learning about how the shoreline has changed, areas of fill, and other threats.



If you are in need of free tickets, contact: info@whollyh2o.org

To sign up for this event, use this link or the "register" button above.

NEW! EPISODE 4 OF THE H2wOah! PODCAST: How Many States of Liquid Water Are there?

If you think there’s only one state of liquid water, think again! In this episode of H2whOa!, hosts Dr. Elizabeth Dougherty and Dr. Ted Hullar examine states of water with Dr. Pablo Debenedetti of Princeton University and hyper-realistic artist Olumide Oresegun. 

Access the podcast using this link or the "Listen Now" button above. Available on Apple, Spotify, Google, and Soundcloud.

King Tides: The Bay in a Midwinter Cosmic Dance

How the alignment of the sun and moon tell us more about the oceans here on Earth

Every so often, typically every January and December, the Bay Area experiences a natural phenomenon known colloquially as the “king tides”, which are essentially higher-than-normal tidal waves. However, in recent years due to the changing climate and rising sea levels, the king tides have transformed parts of the Bay Area into scenes reminiscent of Hayao Mizayaki’s 2008 film Ponyo: flooded highways, towering waves, and the sea knocking on our front doors. This January, we’ll be exploring the mechanics of how king tides work, the impact they have on the Bay Area, and how climate change may continue to shape these tidal events. 

King tide fooding in Marin / South Marin Fire District, SFGATE

Flooded highway / Hayao Miyazaki's Ponyo (2008)

“King tide” is not a scientific term with definitive parameters. Rather, it serves as a general, nonscientific name for the high tides that swell about 1-2 feet taller than average at certain times of year. But how do they actually occur? To understand king tides, it’s important to first understand how the sun, moon, and ocean interact to create tides in general. 

Tides, the natural rise and fall of the ocean, are caused by tidal force — the gravitational force of the moon pulling on the Earth. Markedly high or low tides happen during new moons or full moons when the sun, moon, and Earth align. This is because the added gravitational force from the sun amplifies existing lunar tide effects. These amplified tides are sometimes called “spring tides” — a reference to the “springing” back and forth of the water — and usually occur about twice a month. 

King tides go a step beyond this, the result of an intricate, precise cosmic dance that occurs in midwinter. At this time of year, the Earth reaches perihelion, or its closest point to the sun. In addition, either the monthly full moon or new moon (this year it’s a new moon) causes the moon itself to reach perigee, or its closest point to Earth. When perihelion and perigee occur simultaneously, typically around early January, the already pronounced tidal forces from lunar and solar alignment become even more dramatic, resulting in king tides. 

King tides are predictable, and you can learn more about the Bay Area’s local king tides and king tide predictions through the California Coastal Commission’s California King Tides Project. The first few king tides of the season occurred in early December, and the next few projected king tides are set to occur on January 11th and 12th with highs of about 6.9 feet. 

King Tides at Ferry Gate G, S.F. / California King Tides Project, SFGATE

Now, with an understanding of how king tides work and what they are, we can dive into their terrestrial impacts and how they interact with climate change. 

Since the industrial revolution, development has rapidly spread across the Bay Area, including low-lying areas along our shorelines. During annual king tide events, these areas often flood, damaging infrastructure and pulling chemicals off the land and into the water, similar to how stormwater does. It also poses potential danger to pedestrians, drivers, and homeowners. Roads in Mill Valley, Berkeley, and Alameda are often drowned during the king tide season, and in San Francisco, the Embarcadero is a notorious flooding site. While this phenomenon is fascinating to see, it is best to avoid driving in highly flooded areas or walking while a tide is sweeping through. Sandbagging around the home is also advised if you are concerned about potential flooding.

Beside the more salient dangers to industrial structures, the impacts of king tides are becoming magnified by climate change and rising sea levels. It is important to note that king tides themselves are not a result of climate change; it is the combination of changing weather patterns and sea level rise that are causing them to be more of a threat. 

As storms become more intense due to shifts in weather and climate, king tide floods might be coupled with torrential rain and flash flooding, causing exponentially worse harm and danger. And, as sea levels continue to rise due to melting polar ice, king tides might reach further than before, spreading damage to areas that were previously not at risk. Or, they might pose greater risk to areas that currently flood. In a 2018 Sea Level Rise Guidance report by the California Ocean Protection Council, it was found that water levels around San Francisco are predicted to rise anywhere from 1-3 feet by 2050. According to KQED, the Bay has already risen 8 inches since the mid 19th century. 

Pier 14 flooding 2019 / Jessica Christian, SF Chronicle

However, all is not lost. Though these circumstances and predictions are frightening, there is work being done to remediate potential damage — work that you can take part in, too. 

Despite the damage that the king tides pose on the Bay Area’s coastal areas, they give us the important ability to see what places are most susceptible to sea level rises and flooding, allowing us to figure out where and how to focus protection efforts. Already, officials in Marin County are exploring ways to create wider floodplains in at-risk creeks and build tidal marshes that will help absorb excess water. In 2018, a bond measure in San Francisco was approved by voters to construct a seawall protecting the Embarcadero.

In addition, the California King Tides Project has been encouraging the public to photograph local king tides events, both to help the public gain an understanding of how sea level rise may impact the Bay Area, and also to contribute to a growing record of shoreline changes. To learn more about this initiative and take part, click the link here. 

If you’d like to learn even more about king tides and their impacts in the Bay Area, be sure to sign up for Wholly H2O’s King Tides Walking Waterhoods tour in partnership with the San Francisco chapter of the Sierra Club, happening January 13th. 

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