News

Tillamook County deemed highest landslide susceptibility area in state


By Chelsea Yarnell

cyarnell@countrymedia.net

 

A new landslide susceptibility map created by Oregon Department of Geology and Mineral Industries helps identify regions of the state that may be at risk for future landslides… and Tillamook County has the highest susceptibility in the state.

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“Oregon is prone to landslides,” said Bill Burns, engineering geologist for the Oregon Department of Geology and Mineral Industries (DOGAMI). “This map points us toward priority areas for future in-depth mapping and study of our landslide hazards, and helps Oregonians better understand the potential hazard in their own communities.”

According to a release from DOGAMI, more than a third of Oregon’s land has very high or high landslide susceptibility. Very high susceptibility means the area is an existing landslide; high susceptibility means landsliding is likely. Landslides can be triggered by factors such as intense rainfall, rapid snow melt, and freeze/thaw cycles. In some areas of the state, particularly western Oregon, very high and high susceptibility percentages are much higher.

 

“We have a lot of rain, we have a lot of steep slopes and weak geological [site] especially in Oregon,” DOGAMI Communications Director ALI RYAN HANSEN told the North Coast Citizen.

DOGAMI reports that the new mapping marks the first time since 1982, when the U.S. Geological Survey published a landslide overview map of the United States, that there’s been a look at the landslide susceptibility of the entire state. The accompanying report includes susceptibility percentages for all Oregon counties, incorporated cities, and some watersheds.

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“It really was a good time for us to do this for two reasons: We finally had the modern technology to make this modern map… [and] so many parts of Oregon , especially Western Oregon are susceptible to landslides,” Hansen said.

DOGAMI also believes that the new landslide hazard information can help Oregonians protect themselves and their property. Knowing which areas may be susceptible to landslides helps people identify places to avoid during extreme weather, and helps people determine whether hiring a geotechnical professional to evaluate their property may be necessary.

“It’s good way for the general public to learn about the landslide susceptibility where they live,” Hansen said, especially with the catastrophic damage the Northwest has seen in recent years. “It was something the Oso tragedy brought more awareness to.”

 

The new interactive map can be found at: bit.ly/oregonslido.