City warns of landslide season in Seattle

With heavy rains on the way, the city of Seattle warns landslide season is arriving with them.

“Despite the fact that we have yet to experience widespread flooding or soil saturation this season, October is already much wetter than normal, so it shouldn’t be much of a surprise that landslide season is here,” said said Seattle Public Utilities (SPU) meteorologist James Rufo-Hill, who writes a blog on local weather conditions.

More than an inch of rainfall is forecast for Seattle over the next two days, which is expected to push the area across the official U.S. Geological Survey (USGS) landslide threshold for the first time this year.

“The latest forecast indicates that by tomorrow (Friday) over an inch of rain will fall citywide. SPU neighborhood rain gauges will have recorded nearly two inches in the past three days and nearly four inches over the past two weeks. Those totals are certain to push Seattle beyond the landslide threshold developed by the USGS and SPU,” he said.

Rufo-Hill offered a number of pointers for protecting yourself and your property from landslides:

• If a landslide damages your property and you have an immediate concern for your safety, leave the premises and call 911. If you see uncontrolled street water in a steep slope area, please call SPU’s Operations Response Center, at 206-386-1800.

• Seattle property owners with structures that may be affected by or endangered by a landslide should contact a geotechnical professional for structural evaluation.

• Protect yourself and your property by inspecting sloping areas for indications of slope movement (such as cracks in the ground, and newly tilting trees) and erosion.

• Check your downspouts, to make sure they are functioning and routed to a safe location.

• Be sure that your irrigation system is shut off.

• Keep fill and yard waste off slopes.

You can check out current conditions of the USGS rainfall threshold for landslides here.

Learn more about landslides from SPU here.