California's 2026 El Niño Threat: What Investors Need to Know About Coastal Flood Risks

Another issue lurking in the waters of Southern California’s coastal property markets this winter is the threat of severe flooding in well known locations such as Newport Beach, Long Beach and communities around the San Francisco Bay. Already 12 inches or more higher than just a few years ago, with one of the strongest El Niño events in a century threatening to bring another round of severe flooding to coastal areas, severe flooding at high water could become the new normal for certain areas of Southern California and the Bay Area this winter.

Flooding occurred on the streets of Newport Peninsula and parts of Long Beach in October 2026, even in the absence of hurricane storm surges. The additional 2-3 feet of water elevation resulting from the sea-level rise and severe flooding conditions described above can cause irreversible damage to a beachfront property. It remains to be seen whether or not the typical methods of protecting such a property from flooding (e.g. periodic replenishment of sand) will remain effective in the face of such extreme events.

In the San Francisco Bay Area, there are areas of historic marshlands that have been developed into residential areas, including parts of West Oakland, Alviso and the Canal Area of San Rafael. These are in close proximity to critical infrastructure such as the San Francisco International Airport and sections of U.S. 101. Many of these areas could see flooding of up to 3 feet in height.

And then there is Highway 37, the road that runs through several critical communities. In 2017 and 2023, the road was closed for extended periods of time due to flooding. In the intervening years, a new bridge was planned but not yet constructed. And while a new crossing is ultimately better than the current failing structure, that will not become the case until 2027 or later. The Petaluma River levees that protect agricultural land and critical highways from flooding are also near collapse.

Investors must keep in mind that how long the negative impacts will last in terms of economic impacts, are dependent on how fast mitigation and infrastructure upgrades can be implemented by government agencies. Furthermore, typical measures of protection to flooding may not be effective enough as storm surges from El Niño events are being increased by the steady rise in sea levels. Location and future development plans are key for investors to conduct proper due diligence.

What This Means for Your Portfolio:

1. Carefully research the elevation and historical flood activity of potential investments in Southern California waterfront and other low-lying properties as well as Bay Area properties.
2. Keep up to date on the progress of necessary infrastructure projects (such as a new bridge crossing on Highway 37 and improved flood defenses at SFO airport).
3. Factor in increased cost of insurance and possible disturbance to tenant or customers when calculating return on rental income or resale value.
4. Diversify within coastal California real estate markets to manage the risk of flooding in specific geographic locations.

Beyond the Floodwaters:

California’s coastal flooding risks are becoming bigger issues for investors as they translate into property values over time. How long will it take for these risks to be locked into current market values? Will investors begin to price in these issues more explicitly, or will they underestimate the long-term economic damage for too long?