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Government or official record

SR 530 Landslide Commission Final Report

State of Washington

Where this source supports the record

Each entry separates the article’s editorial relevance note from its exact, section-level claims. A bibliography link without a direct claim is labeled plainly.

  1. Natural disasters · 22 March 2014

    The Oso Landslide

    State Route 530 landslide and Steelhead Haven area · United States

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    Why editors use it here

    Independent state review of hazard knowledge, emergency response, communication, and recommendations.

    1. Quick read

      At 10:37 a.m.

      Reviewed 26 July 2026
    2. Trigger and conditions

      A deep-seated block on the upper slope moved and disintegrated into water-saturated debris.

      Reviewed 26 July 2026
    3. Uncertainty

      Scientists agree that groundwater and preexisting landslide geology were central, while the relative roles of rainfall, river erosion, logging, and other factors remain debated.

      Reviewed 26 July 2026
    4. Why it matters

      Oso shows the gap between knowing that a slope has failed before and conveying what future failure could do.

      Reviewed 26 July 2026