Northern California Coastal Flood Advisory
A coastal flood advisory has been issued for Northern California, including Fremont, effective from Sunday through Tuesday. The advisory warns of potential flooding in low-lying coastal areas due to a combination of high tides and an incoming winter storm.
- The current event is driven by the "coldest storm system of the season," which is expected to bring 2-3 inches of rain to the Sacramento Valley and up to four inches in the foothills by Wednesday. - A wind advisory is also in effect, with southerly winds of 25-35 mph and gusts reaching up to 50 mph, which contributes to the storm surge by pushing more seawater inland. - The flooding threat is amplified by "King Tides," a non-scientific term for the highest predictable tides that occur when the Earth, moon, and sun align, raising water levels one to two feet above normal. - This combination of a winter storm with King Tides has caused significant flooding in the recent past; in early January 2026, a similar event resulted in the highest tides in over two decades, trapping cars in 3-4 feet of water and closing parts of U.S. Highway 101 in Marin County. - In Fremont, the areas most vulnerable to this type of flooding are the Baylands and the south Warm Springs district. - A long-term city report on sea-level rise indicates that a 36-inch rise in the San Francisco Bay would expose the Union Pacific railway, 32 structures, and numerous power lines in Fremont to flooding. - The National Weather Service has specifically warned that the combination of high astronomical tides (spring tides) and storm surge from the current storm will lead to minor flooding in low-lying areas along the San Francisco Bay and Monterey Bay shorelines through Tuesday.
