New Landslide Inventory of Western King County Published

We are pleased to announce the publication of our Landslide Inventory of Western King County.


Landslide Inventory of Western King County, Washington


Lidar-based landslide mapping of a 1,480 mi2 area in western King County and a small portion of Snohomish County inclusive of the City of Bothell produced an updated inventory of landslides in one of the most populated areas of Washington State. Following protocols by Slaughter and others (2017), mapping yielded 2,838 landslides and 1,251 fans covering approximately 4.3 percent of the study area. High landslide density was noted along Puget Sound bluffs, river corridors, and in upland areas of the Cascade Range. This updated landslide inventory will increase awareness of landslide hazards in King County and assist planners, emergency managers, public works departments, and those who live and work where landslides could impact their daily lives.

Suggested Citation: Mickelson, K. A.; Jacobacci, K. E.; Contreras, T. A.; Gallin, W. N.; Slaughter, S. L., 2019, Landslide inventory of western King County, Washington: Washington Geological Survey Report of Investigations 41, 7 p. text, with an accompanying Esri file geodatabase.

You can also view these data and create custom landslide maps on the Washington Geologic Information Portal.

GIS Data for Download

The Survey also maintains two landslide databases: the Landslide Compilation and the new Landslide Inventory. Both datasets are updated on our Portal and are also available for download from our GIS Data and Databases webpage.

The new Inventory dataset follows a protocol that requires high-quality lidar data, available here. So far, the dataset includes landslide inventory and susceptibility data for Pierce County, the Columbia Gorge, and Western King County. We will add new data to this dataset as new inventories are published.

The Landslide Compilation dataset is just that: a compilation of published landslide data from throughout our agency and other published sources, including reconnaissance inventories after large landslide events, geologic mapping, and other watershed studies. Many of the landslides shown in this dataset were mapped without the benefit of lidar. Thus, any new mapping published through the Inventory supersedes what is contained within the Compilation.