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U.S. Geological Survey El Niño Information

Recent News and Information on the 2015–2016 El Niño

Model output from the Coastal Storm Modeling System.El Niño and its Likely Effects on Southern California

Andy O’Neill, an oceanographer and meteorologist with the USGS Pacific Coastal and Marine Science Center, explained what El Niño is and how this year’s El Niño might affect Southern California in a webinar produced by University of Southern California (USC) Sea Grant. Her half-hour presentation opened “El Niño: What to Expect for Southern California,” a professional-development webinar broadcast October 28, 2015 (see other webinars at O’Neill’s clear explanation of the many facets of this complex phenomenon included a description of the Coastal Storm Modeling System (CoSMoS) and its latest extreme-storm flooding projections for Southern California. Many California agencies are eager to use these projections in their El Niño planning.
For more information, contact Andy O’Neill,,

Bluff erosion during the 200910 El Nino undermined the Great Highway guardrail at the southern end of Ocean Beach. Photo by Jeff Hansen, USGS, 2010.El Niño and La Niña Will Exacerbate Coastal Hazards across Entire Pacific

The projected upsurge of severe El Niño and La Niña events will cause an increase in storms leading to extreme coastal flooding and erosion in populated regions across the Pacific Ocean, according to new research by USGS scientists at the Pacific Coastal and Marine Science Center and their collaborators at institutions in Australia, New Zealand, Canada, Italy, Japan, and the United States. These results are independent of projected sea-level rise, which alone could displace up to 187 million people worldwide by the end of the 21st century. Nature Geoscience published the findings on September 21, 2015.

For more information:

Tim Elfers using an echosounder and GPS receiver mounted on a personal watercraft to survey the seafloor just off the beach near the Santa Cruz Beach Boardwalk.Climate Check in our Santa Cruz, California Backyard

Winter storms modified by future climate changes, including sea-level rise, could mean costly damage to harbors, beaches, and businesses, especially during El Niño years, when atmospheric conditions bring heavy rains to the central California coast. The biggest storms tend to hit later in the year when beaches have already been heavily battered. In a populated area that relies on its coastline for much of its revenue—from people such as surfers, beach goers, sailors, kite surfers, divers, and fisherman—there is a great need to understand how big storms can shape and affect the coast. Perhaps storms will alter an important snowy plover habitat, shift a surf break, or erode natural beach protection for waterfront businesses such as those in Capitola. USGS scientists in Santa Cruz have a rare opportunity to work on these issues close to home and collect data that can affect a range of people and businesses within the Monterey Bay region. Studying these changes now will help researchers create models of future climatic changes that will erode and shape our coasts—a valuable tool for city planners, conservationists, and the tourism industry.

Read more about this new study.

Photograph of Berkeley in 2006.El Niño and Landslides

Northern and Central California
The USGS conducts active research on identifying the triggering mechanisms and hazards associated with landsliding. In northern and central California, research efforts have predominantly focused on the San Francisco Bay area, and a number of research products are available that showcase the landslide effects of previous large winter storms to the region, including some related to El Niño events. These reports and maps can be used as examples of what may occur during the upcoming 2015-2016 El Niño season if heavy precipitation occurs. Visit the USGS Landslide Hazard Program's web site on El Niño and Landslides in Northern and Central California.
Southern California
Like the northern part of the state, southern California is well known to be susceptible to landslides. Some are triggered by earthquakes, but more frequently landslides are caused by intense and/or prolonged rainfall. Some, but not all, of the major winter storms that have caused landslide fatalities and property damage in southern California have occurred during El Niño (1997-98 info) conditions. The USGS has a long history of research to identify landslide hazards in southern California. Visit the USGS Landslide Hazard Program's web site on El Niño and Landslides in Southern California.

Other sources of El Niño information

These links were created during and following the 1997–98 El Niño.

Weather Map, 1-Jan-1983Climate

Storm Waves, Capitola, CACoastal hazards

Flooded Cosumnes River, CAFloods

Landslide, San Mateo County, CALandslides

National Oceanic and Atmospheric Administration (NOAA)

NOAA’s El Niño Portal

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Page Last Modified: 20 November 2015 (lzt)