By Daily Mail (U.S.) | Created at 2026-08-07 15:12:17 | Updated at 2026-08-07 17:54:20
3 hours ago
Scientists have issued a dire warning after discovering 6.5 million Americans live on terrain highly susceptible to potentially deadly landslides.
The first nationwide building-level assessment found that 3.8 million properties worth an estimated $1.2 trillion are located in the country's most landslide-prone areas.
Nearly four in five exposed residents are concentrated in Appalachia and along the West Coast, including communities near Seattle, San Francisco and Los Angeles.
West Virginia emerged as the most vulnerable state, with approximately one in five residents living on highly susceptible terrain.
Researchers found that rural Americans face the greatest danger because many live on steep slopes far from emergency services and have fewer resources to recover from a disaster.
In cities, at-risk properties are more likely to be expensive hillside homes occupied by residents with greater financial means.
The threat is expected to grow as housing development pushes farther onto unstable slopes and climate change fuels more intense rainfall, a major trigger for landslides.
Landslides already cause an estimated $3 billion to $6 billion in damage and multiple deaths across the US every year. Most are triggered by intense rainfall or earthquakes, while road construction, excavation and other human alterations can further destabilize vulnerable slopes.
The first nationwide building-level assessment found that 3.8 million properties worth an estimated $1.2 trillion are located in the country's most landslide-prone areas
The findings come from a new database that analyzed 128 million US buildings to reveal for the first time exactly where landslide exposure is concentrated.
The map, created by researchers at the University of Washington (UW), found that although nearly 20 percent of US land is prone to landslides, only two percent of the population, about 6.5 million people, live in those areas.
Nearly 80 percent are concentrated along the West Coast and in Appalachia, with West Virginia recording the largest share of exposed residents.
Joseph Wartman, a UW professor of civil and environmental engineering and the co-creator of the database, said: 'Those concentrations were surprising.
'In a sense, it's good news, because it shows landslide risk to be a localized hazard, which makes it more practical and affordable to address.'
The danger is not distributed evenly, with California recording the largest number of exposed residents.
However, West Virginia faces the greatest proportional threat, with approximately one in five residents and 70 percent of its land in highly susceptible areas.
Appalachian communities are particularly vulnerable because the region’s narrow valleys and steep slopes leave residents with few safe places to build.
Nearly four in five exposed residents are concentrated in Appalachia and along the West Coast, including communities near Seattle, San Francisco and Los Angeles. Above is a landslide in San Clemente, California in 2023
The Appalachian Highlands contain 3.6 million people living in highly susceptible areas, accounting for 55 percent of the national total.
Exposure is concentrated from eastern Kentucky through western North Carolina, with additional hotspots in Pennsylvania’s Ridge and Valley region.
Pennsylvania, New York, Tennessee, North Carolina and Virginia also contain large exposed populations where Appalachian terrain intersects with established communities.
Washington and Oregon combine above-average exposure with substantial populations living along the Cascadia corridor.
Researchers also uncovered a stark divide between rural and urban communities.
Approximately 62 percent of buildings in highly susceptible areas are rural, where residents are more likely to face poverty, limited transportation and long distances from emergency services.
The study identified roughly 732,000 exposed people living in poverty, primarily in the central and southern Appalachians.
In cities, however, landslide-prone areas are often affluent hillside neighborhoods valued for their views, particularly around Seattle, San Francisco and Los Angeles.
Those residents generally have more money and resources to prepare for a disaster and rebuild afterward, although dense development means a single landslide can damage several properties.
Of the 3.8 million buildings in highly susceptible areas, 94 percent are residential. The remainder includes commercial and industrial properties as well as schools, fire stations and government buildings.
Researchers warned that damage to emergency facilities could have consequences beyond the properties themselves by disrupting rescue and recovery operations.
To create the database, researchers combined a high-resolution US Geological Survey susceptibility map with building footprints, occupancy records and Census data covering income, disability, vehicle access and housing conditions.
The resulting tool assessed 128 million structures across the country and classified the terrain surrounding each building as having no, low, moderate or high landslide susceptibility.
Researchers tested the database against 590 verified landslides in Seattle that collectively affected 2,315 buildings.
Every affected structure appeared in the database, while 61 percent had been classified as highly susceptible and another 25 percent as moderately susceptible.
The team also examined 101 landslides associated with Hurricane Helene that damaged 270 buildings.
The database captured 91 percent of those structures, although some buildings located on flatter ground were classified as having low susceptibility because debris had traveled downhill from steeper terrain.
In the most extreme case, landslide debris traveled approximately 0.9 miles from where the slope initially failed, highlighting the danger faced by homes beyond the areas where landslides begin.
The researchers warned against a one-size-fits-all national response because exposed communities have markedly different resources and needs.
