Sea Level Rise

The Humboldt Bay area is experiencing the fastest rate of relative sea level rise on the West Coast. That's because tectonic activity is causing the ground beneath the bay to sink at the same rate that the ocean is rising. According to the California Ocean Protection Council's 2024 Science & Policy Update, sea level in the Humboldt Bay area is expected to rise approximately 1.5-2 feet above 2000 levels by 2060 and 3.9-5.5 feet by 2100.

The primary impacts from sea level rise are increases in flooding, erosion, and rising groundwater. Sea level rise will expand areas vulnerable to flooding during major storms, as well as in the rare but catastrophic event of a major tsunami. The term 100-year flood is used as a standard for planning, insurance, and environmental analysis. But these extreme storms are happening with increasing frequency, in part due to rising seas. Sea level rise will cause more frequent—and more damaging—floods to those already at risk and will increase the size of the coastal floodplain, placing new areas at risk to flooding.

To view sea level rise scenarios for the Humboldt Bay area, visit NOAA's 2022 Sea Level Rise Viewer and go to the local scenario for the North Spit.

Interactive Map of King Tide Photos

The California Coastal Commission's King Tide Photo Project features photos from the Humboldt Bay area and across the state. Anyone can upload photos online or via a smartphone app. Click HERE to upload yours.

Wondering about good spots to view the King Tides around Humboldt Bay? Visit our Humboldt Bay King Tide Photo Project.

Left: Erosion along New Navy Base Road in Samoa during the December 23-24, 2022 King Tides. Photo by Jen Kalt.

Land Is Sinking Fast Along Parts of the Coast, Worsening the Effects of Sea Level Rise

The land at multiple spots along California’s iconic coastline is sinking at startling rates, compounding the flooding risks posed by future sea level rise from Humboldt Bay to San Diego, according to a new study led by scientists at NASA’s Jet Propulsion Laboratory.

The speed of the land sinking, or subsidence, helps show that regional estimates “largely underestimate” sea level rise in parts of the San Francisco Bay Area and Los Angeles. That adds a new layer of complication for cities along the 800-plus miles of coastline preparing for a far wetter future, while some are already dealing with flooding from climate-fueled storms and king tides.

EcoNews Report: Rising Seas and the Future of Humboldt Bay

In the third episode of Humboldt Waterkeeper's special series on communities at risk from sea level rise, we hear from long-time residents and relative newcomers who share their thoughts and concerns about sea level rise. We are also joined by Laurie Richmond of the Cal Poly Humboldt Sea Level Rise Institute, which is a network of academics, tribes, government agencies, NGOs, private consultants, and civic and community groups working to envision the future of our region. How will we adapt to increased flooding and rising groundwater in low-lying areas? Whether we decide to protect certain areas, relocate critical facilities, or figure out how to live with rising water levels, major changes are on the horizon. The good news is that we have time to plan, and a lot of people are thinking deeply about these issues.

Choose your own sea-level rise adventure

California adopted new sea-level-rise guidance for local and state planners today.

TLDR: It won’t be apocalyptic in the short-term, but it’s bad, and you should pick your path now.

By design, the Ocean Protection Council’s document is more diagnostic than prescriptive. It doesn’t really say what to do about existing infrastructure like Big Sur’s portion of Highway 1 that keeps falling into the ocean. Nor does it mention the most foolproof — and controversial — way to reduce risk: “managed retreat,” or simply moving inland.

Rather, it updates sea-level-rise projections, ranks their likelihood and suggests deciding what to do with coastal projects based on their importance and life frame.

Some experts and environmental groups are concerned it doesn’t go far enough in offering managed retreat as an option.

“It feels like a little bit of a worrying trend,” Laurie Richmond, a professor at Cal Poly Humboldt and a co-chair of the university’s Sea Level Rise Institute, said in an interview. “I’m proud of our state, and I think we’re real leaders on a lot of this, and there’s a lot of support for sea-level-rise planning and innovative thinking, but I don’t want us to backslide.”

Keep reading

Hearing from the Californians on the Front Lines of Climate Change

A new paper gives voice to the residents of King Salmon — California’s community hardest hit by rising seas

Due to tectonic activity, the land around Humboldt Bay is sinking, amplifying the impacts of rising oceans. In King Salmon, the seas are rising three times faster than the national average. “It’s easy to think about climate change as something happening way in the future,” says Kristina Kunkel, who recently published a paper with Professor Laurie Richmond on her findings. “Like, ‘maybe we don't have to really think about it much yet.’ But King Salmon shows how it’s happening right now. That’s revelatory, for some people.”

Given how few people had heard from King Salmon’s residents, Kunkel’s advisor Laurie Richmond wanted to ensure that the research wasn’t overlooked.

EcoNews Report: Can We Clean Up Humboldt Bay Before the Sea Rises?

As keen observers are well aware, the industrial legacy of the 20th Century left many contaminated sites around Humboldt Bay. In our second special EcoNews Report on communities at risk from sea level rise, local residents talking about several of the most vulnerable sites: Tuluwat Island, Butcher Slough in Arcata, and the nuclear waste storage site above King Salmon.