SAN FRANCISCO (CBS SF) — El Niño didn’t deliver pounding rain, but it gave California’s coastline a powerful beating during the winter of 2015/16. Rainfall levels were lower than anticipated, but beach erosion was the highest in more than 145 years, according a study released Tuesday by the U.S. Geological Survey.
Scientists studied 1243 miles along the West Coast from Washington to Southern California, making 3-D surface maps, GPS topographical surveys and measuring sand, wave and water levels at each beach, and published their findings online in the journal, “Nature Communications.”
Winter beach erosion on 29 beaches along the California, Oregon and Washington coasts was 76 percent above normal, “by far the highest ever recorded, and most beaches in California eroded beyond historical extremes,” according to the USGS.
“From a water resources perspective, this El Niño was largely considered a dud due to the unusually low rainfall, particularly in Southern California, which received 70 percent less rainfall than in the last two big El Niños,” said USGS geologist and lead author of the study Patrick Bernard. “However, the waves that attacked our coast, generated from storms across the North Pacific, were exceptional and among the largest ever recorded.”
Bernard says the lack of rainfall means the coastal rivers produced very little sand to fill in what was lost from the beaches, so recovery has been slow. For some beaches it could take decades.
The authors say there may be more extreme El Niños like the 2015-16 event in the 21st century, in fact, they may even double. That would not bode well for the people who live and work along California’s beaches. Just recently, the beachfront residents in Pacifica were forced to abandon their homes due to the severe erosion of the nearby cliff face.
According to the study, “this coastal region, home to more than 25 million people, will become increasingly vulnerable to coastal hazards, independently of projected sea level rise.”
“In addition, the risk of extended drought in the Southwest United States is expected to increase significantly in the coming decades, which, if punctuated by the predicted more frequent extreme El Niño events, could increase coastal hazard threats.”