(WSB photo, Alki slide in 2013)

Though our current run of dry weather might lull you into complacency, now that it’s November, it’s landslide season – and West Seattle is often a trouble spot, with so many slopes. Here’s a seasonal reminder from the city:

Did you know that most landslides occur between the months of November and March? As snow melts and rainfall continues to increase throughout the winter, the threat of landslides will continue to rise.

Landslide season is approaching, so the City of Seattle is urging residents to take preventive measures to protect themselves and their property from possible landslides.

Most landslides are caused by water (e.g. rainfall, uncontrolled stormwater) or human activity that increases the weight at the top of the slope or reduces the stability at the bottom of the slope.

With 20,000 Seattle properties (mostly residential) in landslide-prone areas, Seattle’s Department of Construction and Inspections (SDCI) encourages property owners to take preventive measures to protect themselves from landslides by:

Checking downspouts; making sure they are functioning/routed to a safe location
Maintaining drainage systems by clearing away leaves and debris
Inspecting sloped areas for indications of soil movement and erosion
Shutting off irrigation systems and inspecting them seasonally
Keeping fill and yard waste off slopes
Knowing when to seek professional help for hillside projects

Visit our Emergency Management website to understand if you’re at risk and how to be prepared.

Helpful tools include:

Landslide tutorial
Interactive GIS Map
Landslide Prone Area Map
Do’s & Don’ts

If a landslide damages your property and you have an immediate concern for your safety, leave the premises and call 9-1-1. Seattle property owners with structures that may be affected or endangered by a landslide should also contact SDCI at 206-615-0808 so that a building inspector can respond and perform an initial assessment of the structure.

Visit the USGS website to view the current conditions of the USGS rainfall threshold for landslides.

Early next year we will be providing presentations on landslide awareness during our annual Seattle Home Fair in north and south Seattle. More information will be shared in the coming months.