Design and quantification of an extreme winter storm scenario for emergency preparedness and planning exercises in California

The USGS Multihazards Project is working with numerous agencies to evaluate and plan for hazards and damages that could be caused by extreme winter storms impacting California. Atmospheric and hydrological aspects of a hypothetical storm scenario have been quantified as a basis for estimation of human, infrastructure, economic, and environmental impacts for emergency-preparedness and flood-planning exercises. In order to ensure scientific defensibility and necessary levels of detail in the scenario description, selected historical storm episodes were concatentated to describe a rapid arrival of several major storms over the state, yielding precipitation totals and runoff rates beyond those occurring during the individual historical storms. This concatenation allowed the scenario designers to avoid arbitrary scalings and is based on historical occasions from the 19th and 20th Centuries when storms have stalled over the state and when extreme M. D. Dettinger (&) D. Cayan U.S. Geological Survey, Scripps Institution of Oceanography, La Jolla, CA, USA e-mail: [email protected] F. Martin Ralph M. Hughes P. Neiman NOAA/Earth System Research Laboratory/Physical Sciences Division, Boulder, CO, USA T. Das Scripps Institution of Oceanography, La Jolla, CA, USA D. Cox US Geological Survey Multihazards Demonstration Program, Sacramento, CA, USA G. Estes California Extreme Precipitation Symposium, Auburn, CA, USA D. Reynolds National Weather Service, Monterey, CA, USA R. Hartman NOAA/NWS California-Nevada River Forecast Center, Sacramento, CA, USA L. Jones US Geological Survey Multihazards Demonstration Program, Pasadena, CA, USA 123 Nat Hazards (2012) 60:1085–1111 DOI 10.1007/s11069-011-9894-5