Historic high tides have wreaked havoc across Southern California, leading to extensive flooding that has submerged streets, homes, and businesses. Communities from San Diego to the San Francisco Bay Area have experienced the effects of remarkably high water levels, prompting widespread emergency responses and disruptions in transportation.
In Marin County, north of San Francisco, kayakers and paddleboarders maneuvered through normally bustling streets, which had transformed into waterways due to the flooding. Drivers became stranded in their vehicles, requiring rescue from rising waters, while cyclists attempting to traverse the newly formed lagoons found themselves submerged up to their waists. Meanwhile, cities like Newport Beach faced severe challenges as water overwhelmed emergency infrastructure designed to protect against encroaching seas.
Throughout the state, records have been shattered. In areas near Los Angeles and San Diego, tides surged beyond 8 feet, while San Francisco registered its highest reading for October on Wednesday, surpassing a record set just the day before. As a response to the ongoing flooding, the National Weather Service has issued a series of flood advisories and warnings expected to remain in effect for several days.
Forecasters predict significant coastal flooding during high tides in San Diego and Orange counties through Thursday, warning that numerous roads may be closed and low-lying properties, including homes and vital infrastructure, will likely be inundated. In Los Angeles, moderate flood risks are projected to continue into the weekend, albeit with a decrease in tide levels expected after Thursday. As a result, shoreline erosion is anticipated to afflict various parts of the California coastline.
This tumultuous autumn has particularly impacted Southern California, which has faced several instances of extreme flooding in the past two months. The city of Los Angeles recorded 12 coastal flood days in 2026, as documented by the National Oceanic and Atmospheric Administration (NOAA), marking an unprecedented occurrence not seen in the past five decades.
Despite the eventual retreat of the high tides, experts caution that the risks associated with flooding will not diminish. The newly established records may soon be surpassed, particularly as severe consequences from an exceptionally powerful and strengthening El Niño phenomenon unfold in the coming months. Experts warn that this could lead to tides rising several feet beyond those recorded this week.
“What we are seeing now could be the beginning of what could be significantly more disruptive conditions later this year,” stated climate scientist Daniel Swain during an online briefing.
According to Swain, the rising water levels are attributed to thermal expansion resulting from a record-breaking oceanic heatwave, compounded by higher sea levels linked to the climate crisis driven by human activity. He noted that a coastally trapped Kelvin wave—a substantial band of warm water migrating across the Pacific and up the North American coast—has contributed to the rising sea levels, with expectations for more of these phenomena throughout the winter and into early next year.
NOAA forecasts indicate that San Diego, La Jolla, Los Angeles, and Santa Monica face over an 80% chance of experiencing high tide flooding in December. Coastal stations extending from Southern California to the Canadian border fall within a 60-80% risk category for similar occurrences.
Importantly, the flooding witnessed this week is distinct from the anticipated king tides, which represent the highest predicted tides for the year. These extreme water levels are expected to coincide with the busy holiday weekends of Thanksgiving and Christmas and again around January 20-23 next year.
King tides can elevate water levels by an additional foot or two, a dangerous factor already amplified by approximately one foot due to ongoing global warming, the effects of El Niño, and Kelvin waves. When these effects align, they could result in sea levels rising by up to five feet above average in numerous locations, leading to catastrophic flooding risks.
“We are well into extreme territory – and really in record-breaking territory,” Swain emphasized. “That will set the stage for disastrous flooding, should a storm arrive when waters are high.”
The looming El Niño has the potential to trigger extreme weather patterns globally, with California likely to bear the brunt of intensified storms. Southern California, in particular, has a history of heavy rainfall during El Niño years, and this winter's phenomenon, characterized by warmer-than-average equatorial sea surface temperatures, could deliver exceptionally severe storms.
Should a potent storm hit during periods of peak tide, the potential for flooding could be catastrophic. Swain estimates a 30-40% chance of simultaneous high tides and significant storm events occurring this winter, with possibilities for recurrence.
As Southern California grapples with the immediate aftermath of record-breaking high tides, the region remains on alert for what the winter months may bring. With the specter of El Niño looming, officials and residents alike will need to prepare for the continued threat of flooding and the disruptions it may cause in the weeks and months ahead.
Source: The Guardian