Surface Water

Landslide Awareness

Surface Water staff compiled the following information and internet references in an effort to increase landslide awareness for Skagit County residents.

Landslides occur in all U.S. states and territories and can be caused by a variety of factors including earthquakes, storms, volcanic eruptions, fire, and human modification of land. Landslides can occur quickly, often with little notice. The best way to prepare is to stay informed about changes in and around your home that could signal that a landslide is likely to occur.

In a landslide, masses of rock, earth or debris move down a slope. Debris and mud flows are rivers of rock, earth, and other debris saturated with water. They develop when water rapidly accumulates in the ground, during heavy rainfall or rapid snowmelt, changing the earth into a flowing river of mud or "slurry." They can flow rapidly, striking with little or no warning at avalanche speeds. They also can travel several miles from their source, growing in size as they pick up trees, boulders, cars and other materials.

Landslide problems can be caused by land mismanagement, particularly in mountain, canyon and coastal regions. In areas burned by forest and brush fires, a lower threshold of precipitation may initiate landslides. Land-use zoning, professional inspections, and proper design can minimize many landslide, mudflow, and debris flow problems (FEMA).

Landslides & Debris Flows (FEMA)
This site provides information on landslides and debris flows, and how landowners can protect themselves before, during, and after an event.

Landslide Hazards Program (USGS)
The primary objective of USGS's National Landslide Hazards Program (LHP) is to reduce long-term losses from landslide hazards by improving our understanding of the causes of ground failure and suggesting mitigation strategies. Highlights of the page include information specific to the Seattle area.

Landslide Hazard Information for the Puget Sound Region
This site provides additional links and research specific to Seattle. Highlights of the page include tips on selecting a qualified consultant and a partial list of Puget Sound area geotechnical firms.

Department of Ecology Landslide Website
This site offers information on causes and types of landslides, warning signs, and prevention tips.

Department of Ecology Slope Stabilization and Erosion Control Using Vegetation Website
This site provides coastal landowners basic information concerning the nature and use of slope planting techniques to manage soil erosion and shallow seated land movements. Highlights of the page include plating techniques and a coastal property owner checklist for property evaluation.

Surface Water and Groundwater on Coastal Bluffs: A Guide for Puget Sound Property Owners (Department of Ecology, 1995) (PDF)
This document provides coastal property owners general information concerning the management of water on coastal slopes. The publication introduces the relationships between coastal geology, water, and slope stability.

Vegetation Management: A Guide for Puget Sound Bluff Property Owners (Department of Ecology, 1993) (PDF)
This document provides property owners information on the role, benefits, and management of existing vegetation common to steep, often unstable shore sites in the Puget Sound area.

Soil Stabilization and Erosion Control Using Vegetation: A Manual of Practice for Coastal Property Owners (Department of Ecology, 1993) (PDF)
This document provides coastal landowners basic information concerning the nature and use of slope planting techniques to manage soil erosion and shallow seated land movements. Highlights of the page include plating techniques and a coastal property owner checklist for property evaluation.