El Niño, a recurring climate phenomenon marked by above-average sea surface temperatures, when changes in wind patterns allow warmer water to spread across the central and eastern equatorial Pacific, could spell a wet winter for portions of the western and south-eastern US, climate models show. Coastal areas may be at elevated risk of flooding, experts warn.
Climate scientists predict this year’s ‘super’ El Niño, a label assigned when sea surface temperatures climb by at least 2C, will be the strongest of the century. The weather system is expected to intensify in the fall and winter, persisting until early spring 2027, according to the US National Oceanic and Atmospheric Administration (Noaa).
California has a 70 percent-100 percent chance of experiencing above-average rainfall along its coast, according to a model from the European center for medium-range forecasts.
“El Niño is never going to guarantee any particular outcome in any California winter,” Daniel Swain, the UCLA climate scientist, noted at a virtual El Niño town hall hosted by the California state senator Mike McGuire this week. But, he added, a weather event as strong as the one being currently predicted shifts the odds in favor of a wet winter: “That will likely affect and increase the likelihood of coastal flooding, particularly during strong storm events or during king tide events.”
A 1982-83 weather system destroyed 33 oceanfront homes and damaged 3,000 other residences, according to the California coastal commission.
In a 1997-98 El Niño, California experienced massive flooding and 17 storm-related deaths. In more recent history, during the El Niño winter of 2015-16, state officials reported record coastal erosion on California beaches.
“With less beach in front of the coastline, the waves will have even greater impact on the shoreline with more likelihood of flooding and undercutting of cliffs,” said Mark Merrifield of the Scripps Institution of Oceanography, at McGuire’s town hall.
El Niño is not expected to completely erase drought in the US south-west, where some reservoirs are at an all-time low. “It would have to be exceptionally wet,” Dr Joel Lisonbee, senior associate scientist at the Cooperative Institute for Research in Environmental Sciences at the University of Colorado Boulder, told the Guardian in June.
