[REVISION HISTORY]

Pacific Kelvin waves and West Coast sea level rise

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2026-10-09 07:26 UTC → 2026-10-09 23:43 UTC · added ~~removed~~

Pacific Kelvin waves, massive and sustained bulges of warm seawater linked to El Niño conditions, are driving sea level rises along the North American West Coast. These waves occur when trade winds weaken, allowing warm surface water to move eastward and suppress the upwelling of cold, nutrient-rich water. In California, scientists have projected sea level rises of 15 to 30 centimeters as the wave moves north from Mexico. Oceanographer Dillon Amaya previously noted that ‘every two to four inches of sea level rise can essentially double the risk of flooding.’ While the waves are slow-moving—traveling at approximately 10 kilometers per hour—they significantly increase the risk of flooding, coastal erosion, and property damage when coinciding with high tides or storms. Some areas in Southern California, including Dana Point and Laguna Beach, have already reported property damage and uninhabitable homes. As the phenomenon progresses, officials in San Francisco are bracing for up to 30 king tides between late November and January. Governor Gavin Newsom has previously declared a state of emergency to prepare state agencies for potential record-breaking coastal impacts. In Southern California, the risk is further compounded by the expected interaction between Kelvin waves and swells from Hurricane Rachel, threatening vulnerable areas such as Malibu, Dana Point, and San Clemente. The waves are expected to affect Oregon and Washington through February. Beyond North America, these atmospheric and oceanic shifts may eventually impact North Atlantic circulation, potentially affecting weather patterns in Europe and the Balkans. A large Kelvin ~~wave is now expected to reach the California coast around mid-October. This bulge,~~ wave, which originated near the equator and split upon reaching the South American coast, is expected to reach the California coast around mid-October. This bulge could temporarily raise sea levels by 6 to 12 inches, though some scientists suggest levels could rise by as much as 14 inches this winter. Experts note that such events may become more frequent due to global warming. In areas like San Francisco and La Jolla, sea levels have already risen by approximately eight inches over the last century, making this winter a critical test for state infrastructure management. The impact is extending northward; coastal communities around Greater Victoria and parts of British Columbia are being advised to prepare for higher-than-normal sea levels later this month. While significant impacts are not currently anticipated in Canada, the elevated water may exacerbate high tides and storm surges. PreparedBC has recommended that residents near the coast review emergency plans and identify evacuation routes as the phenomenon moves along the West Coast.

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