Atmospheric Rivers

    What is an "Atmospheric River?"

    Atmospheric rivers consist of narrow bands of enhanced water vapor which provide approximately half of the major rainfall in the Russian River watershed.

    Atmospheric River

    Sonoma County Water Agency and Scripps Institution of Oceanography Enter into Partnership to Study Atmospheric Rivers, Drought Relief Initiatives

    The Water Agency has entered into a cooperative agreement with Scripps Institution of Oceanography and the Center for Western Weather and Water Extremes (CW3E) to advance research in ocean science and meteorology.  The research will help define the role of atmospheric rivers in filling Lake Mendocino and potentially offering predictability to retain water without increasing flood risk. The partnership will also develop a feasibility assessment project for the potential use of forecast-informed reservoir operations (FIRO) for Lake Mendocino in cooperation with the US Army Corps of Engineers. 


    Atmospheric River Washington, D.C. Hill Briefing, 7/13/16

    On July 13, 2016 a briefing was held on the Hill in Washington, D.C. for Congressional staff about atmospheric rivers, subseasonal-to-seasonal precipitation prediction needs, related weather forecasting technology, and their potential benefits of water management.  View a photo presentation of the briefing here. The briefing was moderated by Water Agency Director Shirlee Zane and panelists included:

    • Dr. Louis Uccellini, Assistant Administration for Weather Services, National Oceanic and Atmospheric Administration and Director, National Weather Service
    • Dr. Cary Talbot, Program Manager, Engineer Research and Development Center, U.S. Army Corps of Engineers
    • Ms. Jeanine Jones, Western States Water Council
    • Dr. F. Marty Ralph, Director of the Center for Western Weather and Water Extremes, UCSD/Scripps Institution of Oceanography

    Atmospheric river-driven storms can make or break a water year in the West.  An interagency, cross-disciplinary team of experts is exploring the viability of utilizing forecasts of atmospheric rivers and their heavy precipitation in operational decisions at key western reservoirs that have been plagued by drought.  Such forecasts could provide sufficient notice of these events to enable prudent planning and adaptable operation so that water managers would be better positioned to maximize water supply while maintaining public safety.  Additionally, water decisions across the West can benefit from longer lead time information on precipitation from weeks to seasons in advance.  The briefing was hosted by the Association of California Water Agencies, Western States Water Council, Scripps Institution of Oceanography, and the Water Agency.  

    View the presentations from the briefing:


    Atmospheric Rivers in the News

    Weather balloons in Sonoma County carry forecasting promise
    Santa Rosa Press Democrat - February 5, 2017
    The effort is part of an ongoing, 4-year-old initiative undertaken by Scripps’ Center for Western Weather and Water Extremes, for whom Wilson works, in partnership with the Sonoma County Water Agency, the U.S. Army Corps of Engineers and agencies.

    An explanation of Sonoma County's atmospheric river
    Santa Rosa Press Democrat - January 11, 2017
    The water these atmospheric rivers carry can be vast. ... the top of the agenda for Sonoma County's Water Agency, which is responsible for the ...

    'This is a big deal': Storms could spell end to historic drought
    San Francisco Chronicle - January 10, 2017
    ... yes, the drought is over,” said Marty Ralph, director of the Center for ..... The greatly improved reserves are the result of an atmospheric river ...

    Unlocking the West's Weather Maker
    News Deeply - July 19, 2016
    Atmospheric rivers are responsible for a huge share of California's precipitation. Weather expert Marty Ralph explains new efforts that aim to ...


    Lake Mendocino Forecast Informed Reservoir Operations

    These are a few documents that more fully explain efforts to use improved forecasting techniques to increase water supply in Lake Mendocino:


    More Information

    These are a few links that more fully explain Atmospheric Rivers: