Overview of the ARkStorm scenario

Abstract

The U.S. Geological Survey, Multi Hazards Demonstration Project (MHDP) uses hazards science to improve resiliency of communities to natural disasters including earthquakes, tsunamis, wildfires, landslides, floods and coastal erosion. The project engages emergency planners, businesses, universities, government agencies, and others in preparing for major natural disasters. The project also helps to set research goals and provides decision-making information for loss reduction and improved resiliency. The first public product of the MHDP was the ShakeOut Earthquake Scenario published in May 2008. This detailed depiction of a hypothetical magnitude 7.8 earthquake on the San Andreas Fault in southern California served as the centerpiece of the largest earthquake drill in United States history, involving over 5,000 emergency responders and the participation of over 5.5 million citizens. This document summarizes the next major public project for MHDP, a winter storm scenario called ARkStorm (for Atmospheric River 1,000). Experts have designed a large, scientifically realistic meteorological event followed by an examination of the secondary hazards (for example, landslides and flooding), physical damages to the built environment, and social and economic consequences. The hypothetical storm depicted here would strike the U.S. West Coast and be similar to the intense California winter storms of 1861 and 1862 that left the central valley of California impassible. The storm is estimated to produce precipitation that in many places exceeds levels only experienced on average once every 500 to 1,000 years. Extensive flooding results. In many cases flooding overwhelms the state's flood-protection system, which is typically designed to resist 100-to 200-year runoffs. The Central Valley experiences hypothetical flooding 300 miles long and 20 or more miles wide. Serious flooding also occurs in Orange County, Los Angeles County, San Diego, the San Francisco Bay area, and other coastal communities. Windspeeds in some places reach 125 miles per hour, hurricaneforce winds. Across wider areas of the state, winds reach 60 miles per hour. Hundreds of landslides damage roads, highways, and homes. Property damage exceeds $300 billion, most from flooding. Demand surge (an increase in labor rates and other repair costs after major natural disasters) could increase property losses by 20 percent. Agricultural losses and other costs to repair lifelines, dewater (drain) flooded islands, and repair damage from landslides, brings the total direct property loss to nearly $400 billion, of which $20 to $30 billion would be recoverable through public and commercial insurance. Power, water, sewer, and other lifelines experience damage that takes weeks or months to restore. Flooding evacuation could involve 1.5 million residents in the inland region and delta counties. Business interruption costs reach $325 billion in addition to the $400 billion property repair costs, meaning that an ARkStorm could cost on the order of $725 billion, which is nearly 3 ti...

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

“…In these comparisons of unrouted VIC-simulated runoff rates, the extreme events generated in response to ARkStorm range from 50 to 100 year events in most mountain headwaters of southern, central, and (some) northern California river basins, to 500-to greater than 1,000-year events in areas around Los Angeles, in the central and southern Sierra Nevada, and in the Feather River basin of Northern California. From these runoff-generation frequencies and current 100-and 500-year floodplain maps, ARkStorm flood inundations were roughly estimated (Porter et al 2011) and used in interviews with emergency and resource managers.…”

“…The VIC model was also used to estimate recurrence intervals for ARkStorm runoff rates and totals, as discussed in Sect. 5, to provide a basis for the semiquantitative inundations used in ARkStorm evaluations thus far (Porter et al 2011).…”

High-Resolution Downscaled Simulations of Warm-Season Extreme Precipitation Events in the Colorado Front Range under Past and Future Climates*

“…Additional applications in which such detail is ultimately useful is in driving dynamical runoff/hydrology models and creating scenarios of extreme events under certain climate change conditions (e.g., Barsugli et al 2009;Porter et al 2011;Waage and Kaatz 2011). This style of analysis also provides a diagnosis of driving model performance with respect to the skill of simulating extreme precipitation.…”

Tracking an atmospheric river in a warmer climate: from water vapor to economic impacts

“…We then use these high-resolution simulations in a warmer climate as forcing for the hydrology-hydraulic and economic loss models. Our work follows a similar procedure as the US Geological Survey (USGS) Multihazards Project, which used a synthetic but plausible California AR scenario to estimate the human, infrastructure, economic and environmental impacts for emergency preparedness and flood planning exercises (Porter et al, 2010). In our work, we focus on the Chehalis River basin in western Washington to provide an end-to-end model of severe weather, physical impacts and economic consequences of ARs in a warmer climate.…”