How El Niño-driven Kelvin waves could impact the Oregon Coast

Large-scale Kelvin waves—underwater waves linked to El Niño—could temporarily raise sea levels and disrupt marine life along the Oregon Coast and Washington coastline, according to NOAA and Oregon climate expert Larry O’Neill. Kelvin waves travel beneath the surface and are detected by satellites using temperature and sea-surface height anomalies. They can form in the western Tropical Pacific, move east along the equator, then split north and south near South America, reaching the Pacific Northwest. NOAA expects one Kelvin wave already moving north in early October, with additional waves following. O’Neill said each wave can raise sea levels by roughly 6 to 12 inches (up to around a foot depending on location), worsening coastal flooding and erosion when combined with high tides, winter storms, heavy rainfall, and river outflows. The waves can also alter ocean conditions by warming surface waters and pushing colder, nutrient-rich water deeper, limiting upwelling. In the 2015-16 El Niño, a marine heatwave delayed and disrupted Dungeness crab fishing and caused major financial losses for Oregon’s coastal communities.