Local Landslides

Local Landslides

Following the tragic landslide on the west side, we wanted to get a better idea of what kind of risk we may be at here on the east side of the state.

Senior Research Scientist at Pacific Northwest Laboratory Bruce Bjornstad tells Your Local ABC mountains and hills in the area with agriculture on them are at risk for landslides because of irrigation systems.

He said the 530 landslide north of Seattle happened because of recent rain, making the soil damp and heavy and with gravity it all comes tumbling down.

With the dry climate here, that’s not as much of a concern

What is a concern is with all the farm land and irrigation pipes being installed, Bjornstad said often times things are being overwatered, causing excess water to seep through the mountains, leading to unstable soil.

That is what he said caused the 2006 Basin Hill landslide as well as the 2008 Johnson Island landslide in the southern White Bluffs area.

“Along the White Bluffs is a very steep slope, they’re irrigating the farm lands and that’s causing landsliding down them reaching down into the Columbia River,” said Bjornstad.

Luckily people people were not injured in those two landslides, but Bjornstad said there are a few houses at the bottom of the White Bluffs area and he said it’s not the smartest place to live.

People also hike in that area and could potentially be at the wrong place at the wrong time.

He said just simply based on an aerial photo, it’s easy to tell what’s at risk when he can see fracture lines and with enough water and gravity it can all come down.

Bjornstad said before the 1960’s, when local farming wasn’t as big here, landslides were not as much of an issue and photos show the land to be more secure.

All leading him to the conclusion that farming and excess water is what is weakening the hillsides.