The King Tide Is Back in the Bay Area. Here’s What You Can Expect

Updated 12:52 p.m. Friday

The Bay Area’s first king tide of the season will make an appearance this weekend, prompting advisories for flooding and high surf around the bay and up and down the coast.

“King tide” is not a scientific term but a popular one used to describe very high tides followed by very low tides that occur during a new or full moon. In the Bay Area, they occur a couple of times per year, washing up on San Francisco’s Embarcadero and other low-lying spots across the region.

In San Francisco, the king tide will be at its most extreme on Saturday, when the National Oceanic and Atmospheric Administration forecasts the high tide will be 7.01 feet at 10:43 a.m., and the low tide will drop down to -1.51 feet at 5:38 p.m.

The high tides are expected to last through Sunday and could bring flooding to schools, parks, sidewalks and roads along the shoreline.

The National Weather Service has issued a high surf warning for all Pacific Coast beaches until 11 a.m. Saturday. Swimming and surfing are not advised, as large waves can crop up without warning and pull people into the ocean, the agency warned.

A coastal flood advisory is in effect until 4 p.m. Monday. Some road closures are expected this weekend, and the weather service advises against travel in lowland areas unless necessary. If you choose to travel, allow for extra time in case of road closures and never drive around barricades.

Low-lying areas are particularly at risk during king tides, including cities like San Rafael, which is largely built upon reclaimed wetlands that have subsided over the decades.

“A lot of this area is now lower than the bay during high tides,” said Kate Hagemann, San Rafael’s climate adaptation and resilience planner. “It has a bowl shape, which creates quite a lot of risk.”

The city has physical barriers in place to protect against saltwater flooding during high tides. It also has pump stations designed to get rid of rainwater during big storms. While they’re not designed for high tides, they can help if flooding occurs.

Hagemann said some long-time residents are accustomed to the flooding.

“We do have those pockets where, unfortunately, they’re seeing pretty frequent high tide flooding,” she said. “They check the tides themselves and also move their cars and things like that, too, to stay out of the salt water.”

Scientists say the king tide offers a glimpse into the Bay Area’s future, as climate change drives rising sea levels that bring increased flood risk to the region.

“These king tide events really do give us an idea of what we might be seeing in the not-too-distant future,” said Ben Hamlington, NASA’s Sea Level Change Team leader. “This will be our new baseline.”

The San Francisco Bay has already risen approximately eight inches since the mid-1800s and could increase by about a foot more over the next few decades, according to scientists.