Asynchronous landslide seasonality across the United States

Geophysical Research Letters
By: , and 

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Abstract

Mid-range landslide outlooks can facilitate weather-related landslide preparedness and disaster response planning, but seasonal landslide activity remains poorly quantified at continental scales. Leveraging >55,000 reported landslides from across the United States (U.S.), we used circular statistics to quantify landslide seasonality in 67 National Weather Service County Warning Areas (CWAs). We found regional differences in landslide season timing and duration, with transitions between domains variably corresponding to climate class or river basin. We assessed differences in seasonality by movement type for slides, flows, and falls, detecting apparent, but uncertain, differences between slide and fall seasonalities in 27 of 35 (77%) of CWAs with both types reported. In the Pacific Northwest, where long records exist, we found a credible shift toward a later mean landslide season in western Washington from 1990 to 2020, but no trend in western Oregon. Our results can provide emergency planners a resource to assess seasonal landslide probability nationwide.

Suggested Citation

Luna, L., Mirus, B.B., Collins, B.D., and Perkins, J.P., 2026, Asynchronous landslide seasonality across the United States: Geophysical Research Letters, v. 53, no. 9, e2026GL121707, 11 p., https://doi.org/10.1029/2026GL121707.

Study Area

Publication type Article
Publication Subtype Journal Article
Title Asynchronous landslide seasonality across the United States
Series title Geophysical Research Letters
DOI 10.1029/2026GL121707
Volume 53
Issue 9
Publication Date April 29, 2026
Year Published 2026
Language English
Publisher American Geophysical Union
Contributing office(s) Geologic Hazards Science Center - Landslides / Earthquake Geology
Description e2026GL121707, 11 p.
Country United States
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