Landslides disrupt aquatic habitats, damage infrastructure such as roads, utilities, and dams and harm people. Most mountain ranges are susceptible to landsliding due to a number of factors: geologic factors, such as loose soil or the grade of a slope; and hydrologic factors, such as patterns of rain and snow. The effects of climate change, including an increase in heavy rain and snow events, are poised to increase the intensity and frequency of landslides globally.

Landslides can be disruptive, costly to recover from, and dangerous. Thus, Washington state will benefit from improved modeling that helps land managers make more informed decisions to decrease landslide risk – especially in a changing climate. And, as the Washington Cascade Mountains experience landslides across a wide range of climates, vegetation, and topography, work done here is relevant to mountain areas across the globe.

Previous models for understanding landslide risk were based on either statistical methods, drawn from observational data, or physical models, based on the geologic and hydrologic characteristics of the area. Each model has its own strengths and weaknesses: Statistical models tend to integrate different kinds of data, including data on the climate, geology and ecology of the area; but can become outdated and rely on data that is not always available. Physical models, on the other hand, are typically restrictive in the kinds of landslide events they predict as well as the conditions they represent.

The model employed in this study is unique to previous approaches because it integrates both of these approaches. We found that adjusting a physically-based model of landslide initiation using statistical modeling improved the predictability of observed landslides. This new approach has the potential to transform how we conduct regional landslide research. This study will aid resource management decision making and will be incorporated into K-12, undergraduate, and graduate education.

State of Knowledge: Climate Change in Puget Sound. A comprehensive report summarizing research on the likely effects of climate change on the lands, water and people of the Puget Sound region.

Climate Impacts and Adaptation Fact Sheets for Flood Risks. We partnered with The Nature Conservancy and the Floodplains by Design initiative to produce a set of fact sheets to serve as a quick reference on climate change impacts for six Puget Sound rivers. We also produced a fact sheet highlighting a variety of flood risk adaptation actions being taken in Washington State. These seven facts sheets are intended to make climate change information accessible and relevant to resource managers, city planners, engineers and others who need to plan around changing flood risks in their work.

News Article: Flood and Landslide Risk Research Funded by NSF Grant. With the objective of improving flood and landslide prediction, a collaborative research team led by University of Washington Civil & Environmental Engineering (CEE) has received a four-year $1.7 million National Science Foundation (NSF) Prediction of and Resilience Against Extreme Events (PREEVENTS) grant.

Washington State Parks Climate Change Vulnerability Assessment. We worked with the Washington State Parks and Recreation Commission to understand how climate change may affect State Parks’ properties, facilities, operations and state-wide programs. The Vulnerability Assessment will provide the foundation of the agency’s broader climate change preparedness plan and inform future adaptation work.