Landslides can be a dangerous secondary hazard following a severe storm. According to the U.S. Geological Survey, landslides are a serious geologic hazard common to almost every state in our country. It is estimated that in the U.S. they cause in excess of $1 billion in damages and up to 50 deaths each year.
The power of these land movements was evident during the severe winter storms that struck the Puget Sound region in December 1996 and January 1997. Heavy snowfall was followed by a warming trend that caused quick melting, runoff and flooding, followed by a period of rain. This led to more than 100 slides in King County over the subsequent two-month period.
Although landslides can and do occur in almost any part of the state, geographic King County and the Puget Sound Basin (including Snohomish and Pierce counties) are especially vulnerable due to our urban environment and unique geological conditions. Because of our high population density and the fact that many structures are built either on top of or below bluffs and slopes subject to landslides, more lives are endangered during these land movements and there is a greater potential for damage or destruction to private and public property.
Many of the major valleys and shoreline bluffs of Puget Sound are bordered by steeply sloping, unconsolidated glacial deposits that are highly susceptible to landslides. Other vulnerable areas include the Cascade Mountain passes leading to eastern Washington . As a result, allowing for the possibility of a landslide occurring in our area is an essential component to your family emergency plan.
Source: King County Office of Emergency Management
Learn more about landslides and what you can do to protect you and your property:
Use the following links and recorded messages to keep on top of weather conditions and climate trends that could potentially lead to destructive landslides: