Landslides are a natural part of Oregon’s geology. In Washington County, the Coast Mountain Range is especially prone to landslides that impact our transportation network.
When you hear about a landslide, you may think of a rapidly moving downhill flow of earth. While some landslides are fast-moving destructive flows, others move slowly. They can range from moving a few feet every year to a few feet over several years.
Landslides are most common during the rainy winter season on steep slopes with weak rock. Intense rainfall can saturate the soil, make slopes less stable. This triggers landslides.
Roads cutting through slopes can also make them more unstable. We know that landslides are bound to impact our transportation network, so we keep an eye out for signs that they have started. Cracks in the asphalt and high levels of erosion can be signals that a landslide is active. We monitor spots where we know there may be landslide activity to determine if action is needed.
Our goal is to keep our roadways safe for travelers. We work on repairs and preventative stabilization projects to make sure that our roads remain open. If you see signs of a landslide, travel with caution and let us know by submitting a Request a Road Service.