City monitoring unstable hill in Peaceful Valley

A hillside on the border of Peaceful Valley and Browne’s Addition isn’t at immediate risk of collapse, but it remains unstable and will require a long-term fix, according to city officials.

The city has hired geotechnical engineers to help it track the gradual shift of a hill on the south side of Clarke Avenue in Peaceful Valley. In some places, engineers measured about 3 inches of movement between last Tuesday and Thursday.

Several homes sit atop the hill, on Riverside Avenue in Browne’s Addition.

“At this point we’re not getting concerns from (engineers) about the buildings up on Riverside above,” said Marlene Feist, a city spokesperson. “Right now the movement has nearly stopped because the cold weather is literally freezing up the moist soil right now.”

The city has piled dirt behind a rock retaining wall near the corner of Clarke and Elm Street in an effort to support it. Both of the roads near the hill have been closed to traffic and will remain so for the foreseeable future.

No homes have been evacuated, as most of the property in the area is vacant and owned by the city or Avista.

“We’re watching the properties immediately above, but the slide plain is localized and we don’t have any indication it goes beyond where we’ve been working on,” Feist said.

Last month, more than 8,000 homes in Peaceful Valley and Browne’s Addition lost power after a Ponderosa Pine on the hillside fell onto transmission lines.

Crews are expected to begin work Friday to clear other trees that are leaning and believed to be at risk of falling, Feist said.

The city has already installed survey points to monitor surface movement and plans to install subsurface measuring devices to measure shifts further below.

“As we’re defining what the permanent solution will be, we want to measure not just how the surface of the ground is moving, but underneath,” Feist explained.

Editor’s note: This story was updated on Feb. 13 to correct the spelling of Clarke Avenue.