New Scientific Study Reveals Widespread Landslide Pathways Driven by Rainfall Intensity, Soil Saturation, and Snowmelt

Scientists at Northwestern University and the University of California, Los Angeles (UCLA) have collaborated to develop a new process-based framework that provides a more accurate and dynamic approach to landslide prediction over large areas. This new approach integrates various water-related processes with a machine-learning model, accounting for diverse and sometimes compounding factors. The framework, applied to more than 600 landslides in California, successfully identified the conditions that caused 89% of the events. The research aims to improve early warning systems, inform hazard planning, and enhance strategies for climate resilience in regions vulnerable to landslides.

Key Takeaways:

• The new scientific study reveals three main pathways that led to the California landslides: intense rainfall, rain on already saturated soils, and melting snow or ice.
• Heavy, rapid downpours caused approximately 32% of the landslides.
• Roughly 53% of the landslides occurred after moderate rain fell on soils already saturated from previous storms.
• About 15% of the landslides were linked to snow or ice, with rain accelerating the snowmelt or ice thaw.
• Researchers developed a metric called "water balance status" (WBS) to assess when there is too much water in a particular area, which is more likely to experience landslides.
• The scientists applied a machine-learning technique to group together similar landslides based on their sites' specific conditions, identifying a significant majority (89%) of California's landslides occurring in areas where the WBS was positive.
• This new approach to landslide prediction could help improve early warning systems, inform hazard planning, and enhance strategies for climate resilience in regions vulnerable to landslides.
• The research has implications for understanding the complex factors driving these destructive events and ultimately saving lives and preventing damage.

Statistics:

• Approximately 89% of California's landslides occurred in areas where the water balance status (WBS) was positive.
• Heavy, rapid downpours caused around 32% of the landslides.
• Moderate rain falling on soils already saturated from previous storms triggered roughly 53% of the landslides.
• About 15% of the landslides were linked to snow or ice, with rain accelerating the snowmelt or ice thaw.

Sources:

• Current: https://www.jpl.nasa.gov/news/nasa-study-finds-climate-extremes-affect-landslides-in-surprising-ways/
• Simulating a ‘parade' of storms: https://news.northwestern.edu/stories/2025/07/identifying-landslide-threats-using-hydrological-predictors/
• Research paper: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2025GL115912
• Hydrological predictors: Identifying landslide threats: https://www.digitaljournal.com/world/hydrological-predictors-identifying-landslide-threats/article