6.5 million Americans face landslide risks – a new database shows where they live

Landslides cause an estimated $3-6 billion in damage and multiple fatalities annually in the United States. Those numbers could easily increase as housing needs spur development in landslide-prone areas, and as climate change increases the severity and frequency of heavy rains, which are often a trigger. Despite the threat, there has never been a systematic, nationwide accounting of who is most at risk from landslides.

The new Landslide Exposure Database is the first resource to map building-level landslide risk for the entire U.S. The database, developed by University of Washington researchers, rates 128 million buildings by landslide susceptibility, and uses socioeconomic data to assess residents’ vulnerability to the dangers and disruptions caused by landslides.

According to the analysis, roughly 6.5 million people live in landslide-prone regions; most of those people are concentrated in Appalachia and along the West Coast. Urban residents of landslide-prone properties tended to be more affluent and resilient, whereas rural residents in at-risk areas tended to be less resourced and more vulnerable to the impacts of a landslide.

The results give government agencies and emergency managers a way to prioritize resources for landslide education and mitigation, and can also help individual residents understand their own risk.

“As a community of landslide researchers, we have spent almost all of our time studying the physical geography of landslides,” said Joseph Wartman, a UW professor of civil and environmental engineering and the co-creator of the database. “But we never considered the human geography. Now we can answer some very important questions about who is exposed.”

Wartman and his team published their findings July 29 in Earth’s Future. They also posted the full database online along with user-friendly tools to help nonscientists browse the results.