Flooding on Avenida del Rio in San Diego after a storm in January 2016.​

El Niño is a climate-related phenomenon that occurs across the tropical Pacific Ocean every two to seven years. Sea surface temperatures along the equator warm, often bringing wetter winters to southern California with above normal precipitation and frequent storms from December through March. Previous El Niño events in 1982-83 and 1997-98 resulted i​​n heavy precipitation, record flooding and coastal erosion in San Diego. The 2015-16 El Niño developed into one of the largest events on historical record, which raised concerns for potential storm-related impacts and coastal damage such as erosion, sinkholes, and flooding over roads built in the San Diego River floodplain.

The recurring nature of El Niño provides an opportunity for national and local decision makers and communities to prepare for extreme events, develop and implement mitigation strategies, and plan local responses. We d​​eveloped a research plan focusing on the city of San Diego to determine the degree to which lessons identified during previous El Niño events had become lessons learned, which is a characteristic of an El Niño ready city (ENRC). We reviewed strengths, challenges, and opportunities in San Diego’s El Niño preparatio​​n during historical and contemporary El Niño events. Areas that are prone to weather extremes may benefit from ENRC practices, such as providing more effective management for hazardous threats and bridging mitigation efforts with sustainable development. This encourages the need to broaden forecasts of a specific event toward a holistic approach that includes all available information including historical accounts of El Niño-related socioeconomic and physical impacts. ​​

Christina Stewart (SDSU, BS '16) and Tracy Nishikawa (University of 

Colorado, Boulder) interview Alex Tardy (NOAA).​​​​

The 2015-2016 El Niño was predicted to be the largest El Nino event on historical record with possibly a greater impact than the 1982-1983 and 1997-1998 events. We conducted surveys and interviews with local agencies and collected data and info​rmation to understand levels of preparedness. Our research team met with agencies such as the San Diego County Office of Emergency Services, the City of San Diego Department of Transportation and Stormwater, the San Diego National Weather Service (SDNWS), the City of San Diego Lifeguard Department and attended local El Niño meetings. We found that knowledge and climate predictions, primarily available from the San Diego National Weather Service (SDNWS) and the University of California, San Diego (UCSD) Scripps Institute of Oceanography (SIO), are used to prep​are and pre-develop plans in the event of an emergency. El Niño warnings are widely disseminated to the public through media outlets such as the television news, radio, city of San Diego websites, social media (e.g., Facebook, Twitter, and YouTube), and mobile alert messages for smartphones. 

​To understand public perceptions of El Niño, we ​​conducted a literature review of ~5,200 media articles (online news items, printed newspaper articles and transcripts of radio programs) published over the last four decades (1980 to 2016) and assigned them to categories that reflect prediction an​​d forecasting, preparation and maintenance, economic impacts and damage, policy and community impacts. ​​

Lessons Learned in San Diego

• Historical El Niño media shows an overall increase in maintenance and preparation articles over the last four decades (1980-2016). Heightened publicity show​​s increased importance and awareness of El Niño events and consequences.


A section of Alvarado Creek, a tributary to the San Diego River, is an example of an urban channel with non-native vegetation and refuse that frequently floods during winter storms due to decreased channel capacity.
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• ​Environmental permitting to clean storm channels and drains impeded prompt action for El Niño preparedness. Normally permitting can take up to two years,​​ unless it is declared a state of emergency. This indicates a need for prioritizing the continuous maintenance of storm channels.

• The 2015-16 El Niño-strengthened jet stream traversed primarily across nor​thern California and the Pacific Northwest, rather than southern California, bringing significantly less rainfall than anticipated. Predicting El ​Niño storm events remains a challenge and this uncertainty complicates precautionary mitigation strategies and procedures. 

• Local agencies noted minimal interagency communication and collaboration during previous El Niño events. In anticipation of the 2015-16 El Niño, agencies initiated more communication and developed pre-plans for emergencies such as flooding to improve preparation and response times.
  

• Agencies expressed a critical need for the most recent and up-to-date information and data to pr​​ovide adequate lead-time for pre​​paration actions.

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​The research team visiting the U.S.-Mexico border.

 

Tijuana, Mexico, after a storm in January 2016. 

​In January 2016, the research team also traveled to Tijuana, Baja Californi​​a, Mexico to discuss El Niño consequences and preparation with the Tijuana Civil Protection Department. Moving forward, we will continue to research a cross-border comparison with Tijuana, Baja California, Mexico, led by Fernando Briones (CCB Rese​arch Associate). Although geographically and climatologically simila​r, the infrastructure, policies, a​nd data available for Tijuana and San Diego decision makers to implement long-term preventative actions ​​are diverse. Highlighting the complexity of El Niño ready cities will improve and b​roaden our knowledge of disaster reduction and cities capacities to prepare for these hazards.​

Professors, researchers, and undergraduate stude​​​​nts at San Diego State University and the Consortium for Capacity Building (CCB) at University of Colorado, Boulder contributed to this project. Preliminary work was presented at the San Diego State University Student Research Symposium, an International Mid-Course Workshop for the "El Nino Readiness Portal Project 2016" in Bangkok, Thailand, which focused on the framework for El Nino Ready Nations (http://elninoreadynations.com/), and the 2016 American Geophysical Union Fall Meeting.

Dr. Alicia Kinoshita​ ​is an Assistant Profess​or of Civil, ​Cons​​truction, and Environmental En​gineering​​​ at San Diego State University. Christina N. Stewart​ is a recent graduate of San Diego State University. Drs. Tracy Nishikawa and Mich​ael H. Glantz are with Consortium for Capacity Building at University of Colorado, Boulder​​. COAST provided funding for this project: Rapid Response Funding Program​ Award# COAST-RR-2015-007, December 2015.