Washington State Landslide Could Affect Several Families, Leads To Evacuations

A growing tension crack on a ridge in Yakima County, Washington State, has propelled a number of residents living below it to evacuate their homes fearing a landslide.

Authorities predict the crack on Rattlesnake Ridge could prompt the landslide by the end of February, and which would slam directly into the neighboring Interstate 82 and Yakima River.

About 80 percent of the around 50 residents living near Thorp Road below the ridge have left, reports said. However, some people in the valley have refused to heed the advice of officials to evacuate and decided to stay put in their homes since their lives are inherently rooted in the area.

Some expressed concern on the situation, but said they couldn't move due to lack of money, ABC News reported.

The crack which was first noticed in October last year has significantly increased over the last months, and geologists said about 4 million cubic yards of land has moved, ABC News reported.

The Yakima County Office of Emergency Management has put the area near the ridge on a Level 3 recommended evacuation warning.

This wouldn’t be the first time a landslide is predicted to slam the Yakima County. In 2009, a landslide in Nile Valley destroyed parts of Highway 410, triggering flood in the Naches River and destroying houses.

Residents also told the Seattle Times they were scared of a rerun of the landslide in Oso, Washington, in 2014, where 43 people were killed.

However, opinions are divided among experts whether the landslide will fall on the interstate and the river.

George Machan, a senior associate geotechnical engineer with Cornforth Consultants hired by AK Anderson Quarry — which runs a quarry on the ridge, said most of the material in a slide would be trapped in the quarry and not reach the highway or the river, News Tribune reported.

"There's an extremely remote possibility that it's going to get into the river," Machan said.

However, Bruce Bjornstad, an expert in the geology of Central Washington, warned that the landslide could pose a greater threat to Interstate 82 and the Yakima River, the Seattle times reported.

According to the Seattle Times, Bjornstad, a retired geologist from the Pacific Northwest National Laboratory, said the situation in the county consists all the elements needed for a landslide.

“When, and if, that thing goes, it could wipe out dozens of cars on the interstate, it could potentially dam the river and affect that whole valley,” he added.

According to the Seattle Times, the landslide is threatening a slope where gravel mining has been underway for years, raising obvious questions about the cause and effect of mining in the region, said University of Washington geomorphologist Dave Montgomery.

Cornforth Consultants conducted an analysis in October last year which revealed that removing weight from a rock wedge might have contributed to movement within a slide zone on the ridge.