A TALE OF TWO SLIDES: A COMPARISON OF THE OSO AND LEDGEWOOD-BONAIR LANDSLIDES

In March of 2013, a small, coastal, Whidbey Island neighborhood experienced a significant landslide that damaged one property and impacted several others. While this slide, dubbed the Ledgewood-Bonair landslide, resulted in no loss of life, the phenomenon is far from unusual in Washington State. A year later, following the slide in Whidbey, the community of Oso experienced a larger, and considerably more devastating, landslide that resulted in great loss of life and property damage. Although both slides occurred in different geologic settings, their underlying processes echo a trend that can be found throughout western Washington; this composition results in a geologic setting predisposed to sudden, catastrophic earth movement proximal to human populations.

Efforts to mitigate these hazards by educating the public about their likelihood have been in place for some time. However, recent history suggests the ineffectiveness of public hazards education as it stands. The focus of this report is investigating this phenomenon by analyzing comparatively the lessons of the Oso and Ledgewood landslides.