King tides are coming soon. Here’s when to expect the season’s highest waters

Like “atmospheric rivers” and “heat domes,” “king tides” were something few Californians had heard of until a few years ago. But while the term is relatively new, king tides have been around as long as the sun, the moon and the oceans.  

Starting next week, the first of the season’s super tides will hit the Bay Area. 

King tides are simply royal branding for the highest—and lowest—tidal events of the year. The term was first coined in Australia in 2009, after the country saw its highest seasonal tides in nearly 20 years.

When the sun and moon line up in early winter, the combined gravitational pull translates to high tide marks that can reach 7 feet and contribute to flooding in low-lying areas, especially when they hit during or after storms. California typically experiences three or four king tides every winter, with each one lasting four to five days.

Unlike the intermittent drought and heavy downpours California has experienced in recent years, king tides occur naturally and are not a result of climate change. However, scientists say these “supertides” provide a glimpse of how rising sea levels will eventually affect coastal places. To that end, the California Coastal Commission’s King Tides Project invites people to snap photos of rising waters in their areas during king tides, which they can upload into a statewide photo map.

Unsurprisingly, king tides are most likely to flood neighborhoods along the Pacific Coast and near the shore of the San Francisco Bay. The California King Tides Project map shows where users have reported an impact from high tide levels around the Bay Area. 

Roadways and paths in bayside communities such as Mill Valley, Berkeley, Alameda and Palo Alto are notorious for being covered by king tide waters.

In San Francisco, king tides can cause large waves to crash onto the Embarcadero and flood the bay shore in Bayview-Hunters Point. (The high waters also make the Exploratorium’s Wave Organ near Marina Green play its gurgly thumps and gongs louder and weirder than at any other time of year.)

According to the National Oceanic and Atmospheric Administration, king tides will hit the Bay Area on the following dates:

Though the first set of high tides will arrive on Monday, the 10-day weather forecast does not predict measurable rain until the following weekend, which should rule out any danger of flooding.

Regional officials advise Bay Area residents to take the following precautions during king tides: