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.

NEW! Now you check out our interactive map of two sea level rise scenarios for the Humboldt Bay Area! Featured are scenarios showing 1- and 2-meters above Year 2000 water levels. For many years, these have been static maps with no simple way for the public to examine points of interest. Now, people wondering if their neighborhood is at risk can zoom in on locations and see street names, etc.

San Francisco: a Test Case for Coping with Rising Seas

2/1/13

Parts of New York and New Jersey are still reeling from Superstorm Sandy, an event that brought climate change and the threat of sea-level rise front-and-center. It's a looming problem for all coastal cities, and one that San Francisco has been pondering since long before Sandy struck. Along San Francisco’s western shore, the Ocean Beach Master Plan is a kind of test case for sea-rise planning. It calls for big changes, including a strategy known as managed retreat.

Biggest tides of the year set to hit California

12/12/12

If you head down the beach this week, or wander along the edges of San Francisco Bay, you may just be witnessing California's future.

The ocean is getting closer.

East coast flooding: Wake up call for Humboldt County

11/28/12

This year America watched sea levels rise and the ocean flood cities across the east coast in late October. Humboldt County faces a similar threat.

Mid-November to early December is when flood risk is the highest. A storm during the high tides of that time can overtake the dikes around Humboldt Bay, flood the area and cost the county millions of dollars to recover.

Supervisors back study of rising sea; Bay infrastructure threatened

10/10/12

The county is looking at ways to protect coastal communities on Humboldt Bay threatened by rising sea levels and aging dikes. The Board of Supervisors on Tuesday voted unanimously to support a recent application for a $250,000 Coastal Conservancy grant that would allow nonprofit Coastal Ecosystems Institute of Northern California to adapt planning and technical studies associated with sea level rise in Humboldt Bay.

Aldaron Laird of Trinity Associates said at Tuesday’s meeting that the first phase of the project — the first comprehensive mapping of Humboldt Bay, funded by the Coastal Conservancy — was complete. Seventy-five percent of Humboldt Bay’s 102 mile shoreline is artificial, Laird said, meaning it needs maintenance.

Laird said Humboldt Bay has the highest rate of sea level rise on the West Coast and showed examples of crumbling dikes and shoreline areas that already flood yearly.

Harbor district Director of Conservation Division Dan Berman said it was an important issue for the district, adding that even if sea level rise goes more slowly than expected, it’s already a problem on the bay.

Rising Seas Pose Risks Around Humboldt Bay

Thousands of acres of former tidal wetlands currently at or below sea level around Humboldt Bay—including most of Manila, Samoa, Fairhaven, some residential and commercial areas of Eureka and Arcata, and many agricultural lands near the bay—are at risk of increased flooding in the coming years. 