Dale Cox

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 storms have arrived in rapid succession. Dynamically consistent, hourly precipitation, temperatures, barometric pressures (for consideration of storm surges and coastal erosion), and winds over California were developed for the so-called ARkStorm scenario by downscaling the concatenated global records of the historical storm sequences onto 6- and 2-km grids using a regional weather model of January 1969 and February 1986 storm conditions. The weather model outputs were then used to force a hydrologic model to simulate ARkStorm runoff, to better understand resulting flooding risks. Methods used to build this scenario can be applied to other emergency, nonemergency and non-California applications.

The ShakeOut scenario: A hypothetical Mw7.8 earthquake on the Southern San Andreas Fault

In 2008, an earthquake-planning scenario document was released by the U.S. Geological Survey (USGS) and California Geological Survey that hypothesizes the occurrence and effects of a Mw7.8 earthquake on the southern San Andreas Fault. It was created by more than 300 scientists and engineers. Fault offsets reach 13 m and up to 8 m at lifeline crossings. Physics-based modeling was used to generate maps of shaking intensity, with peak ground velocities of 3 m/sec near the fault and exceeding 0.5 m/sec over 10,000 km2. A custom HAZUS®MH analysis and 18 special studies were performed to characterize the effects of the earthquake on the built environment. The scenario posits 1,800 deaths and 53,000 injuries requiring emergency room care. Approximately 1,600 fires are ignited, resulting in the destruction of 200 million square feet of the building stock, the equivalent of 133,000 single-family homes. Fire contributes

Developing a Scenario for Widespread Use: Best Practices, Lessons Learned

87 billion in property and business interruption loss, out of the total

Special Issue on the ARkStorm Scenario: California’s Other Big One

191 billion in economic loss, with most of the rest coming from shake-related building and content damage (

Application of an extreme winter storm scenario to identify vulnerabilities, mitigation options, and science needs in the Sierra Nevada mountains, USA

46 billion) and business interruption loss from water outages (

The ShakeOut Scenario

24 billion). Emergency response activities are depicted in detail, in an innovative grid showing activities versus time, a new format introduced in this study.

Overview of the ARkStorm scenario

The ShakeOut Scenario is probably the most widely known and used earthquake scenario created to date. Much of the credit for its widespread dissemination and application lies with scenario development criteria that focused on the needs and involvement of end users and with a suite of products that tailored communication of the results to varied end users, who ranged from emergency managers to the general public, from corporations to grassroots organizations. Products were most effective when they were highly visual, when they emphasized the findings of social scientists, and when they communicated the experience of living through the earthquake. This paper summarizes the development criteria and the products that made the ShakeOut Scenario so widely known and used, and it provides some suggestions for future improvements.

The ShakeOut Earthquake Scenario - A Story That Southern Californians Are Writing

At the request of the U.S. Congress’ House Appropriations Committee, the U.S. Geological Survey developed a comprehensive multidisciplinary coastal program, including a research agenda designed among other things to address the most critical issues of coastal and marine geology in the southwestern United States (USGS 2006). As shown by Ralph et al. (2006) and Ralph and Dettinger (2011, 2012), atmospheric rivers are among the principal drivers of several critical physical processes in the coastal systems of the southwestern United States. An atmospheric river is a lowaltitude jet of warm moist air that originates over the midlatitude North Pacific Ocean and transports that moisture to California, where much of the moisture is released as rain and snow that falls on the state. Beginning in fall 2010, the U.S. Geological Survey’s Multihazards Demonstration Project (MHDP) studied the potential impacts of severe winter storms in the context of a disaster scenario: a depiction of a particular hypothetical but realistic storm, explored in sufficient detail that citizens and decision makers can understand its processes, and prepare for and mitigate its consequences. After creating this scenario, dubbed ARkStorm, MHDP’s mission was subsequently expanded to include the western United States, and the project has been renamed Science Application for Risk Reduction (SAFRR). This scenario and others like it provide insight into society’s disaster vulnerability that structural analyses and catastrophe risk models do not. While scenarios tend to be blind to outcome probability distributions (they provide little information for risk-based decision making) and can involve the application of judgment, they can focus deeply on a single event and involve numerous experts who are familiar with different aspects of the relevant disciplines of science, engineering, and social science. That is, as a single (by design) exceptionally challenging event, a scenario can be explored in considerably more detail with a wider range of experts than can probabilistic depictions of risk. They capture interactions among systems and between systems and people, and depict how recovery unfolds over time. They can illuminate how human behavior affects damage and recovery. They measure societal interests in terms of dollars, deaths, and downtime. They inform decision making for planning, mitigation, response, and recovery. Scenarios invite collaboration among experts in different disciplines to recognize and analyze unchartered failure mechanisms, such as the flooding of highvoltage transformers with long-duration replacement requirements. SAFRR is not new in creating planning scenarios. The National Oceanic and Atmospheric Administration (NOAA), the California Geological Survey, the U.S. Army Corps of Engineers, FEMA, and others have created planning scenarios or modeling tools for earthquakes, hurricanes, floods, and other disasters (e.g., Algermissen et al. 1972; Steinbrugge et al. 1987; FEMA 2004; Scawthorn et al. 2006). Three unusual features of SAFRR’s scenarios, including ARkStorm, are that they employ innovative science, are created in large multidisciplinary collaborations with the stakeholders whose assets are at risk, and incorporate extensive multimedia and other outreach efforts. The present volume summarizes some of the findings and innovations of the ARkStorm project. The works presented here address aspects of the scenario that the full report (Porter et al. 2010) does not. A multidisciplinary team of 118 researchers and practitioners from 56 agencies generated the ARkStorm scenario. They evaluated the potential for flooding, severe winds, coastal inundation, landslides, physical damage to buildings and lifelines, agricultural impacts, insurance losses, evacuation planning, traffic, business interruption, environmental and health issues, and public policy. Readers interested in the full, broad study are referred to the USGS Open File Report on the scenario (Porter et al. 2010). The present introductory paper provides brief summary of the scenario. It draws, to some extent, upon intellectual contributions from all of the authors and other contributors to Porter et al. (2010).

Get your science used—Six guidelines to improve your products

In the Sierra Nevada mountains (USA), and geographically similar areas across the globe where human development is expanding, extreme winter storm and flood risks are expected to increase with changing climate, heightening the need for communities to assess risks and better prepare for such events. In this case study, we demonstrate a novel approach to examining extreme winter storm and flood risks. We incorporated high-resolution atmospheric–hydrologic modeling of the ARkStorm extreme winter storm scenario with multiple modes of engagement with practitioners, including a series of facilitated discussions and a tabletop emergency management exercise, to develop a regional assessment of extreme storm vulnerabilities, mitigation options, and science needs in the greater Lake Tahoe region of Northern Nevada and California, USA. Through this process, practitioners discussed issues of concern across all phases of the emergency management life cycle, including preparation, response, recovery, and mitigation. Interruption of transportation, communications, and interagency coordination were among the most pressing concerns, and specific approaches for addressing these issues were identified, including prepositioning resources, diversifying communications systems, and improving coordination among state, tribal, and public utility practitioners. Science needs included expanding real-time monitoring capabilities to improve the precision of meteorological models and enhance situational awareness, assessing vulnerabilities of critical infrastructure, and conducting cost–benefit analyses to assess opportunities to improve both natural and human-made infrastructure to better withstand extreme storms. Our approach and results can be used to support both land use and emergency planning activities aimed toward increasing community resilience to extreme winter storm hazards in mountainous regions.