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The Spokesman-Review Newspaper
Spokane, Washington  Est. May 19, 1883

Rattlesnake Ridge still moving, but landslide predictions have stopped

In this Monday, Jan. 8, 2018, photo, James Gleeson, a surveyor with the Washington State Department of Transportation, takes measurements from the shoulder of Interstate 82 to monitor a slow-moving landslide on Rattlesnake Ridge beyond in Union Gap, Wash. (Elaine Thompson / Associated Press)
By Alec Regimbal Yakima Herald-Republic

Due to a sharp decrease in how quickly 20 acres are accelerating down Rattlesnake Ridge, officials say it’s difficult to predict when the impending landslide will happen.

“We’ve pretty much taken the end date off the table; it’s too hard to predict when it will occur,” said Joe Smilie, a spokesman with the state Department of Natural Resources.

Late last year, officials predicted the landslide could occur by mid-January. That estimate was later revised to sometime in early March. Officials now say the slide – which is moving at a rate of 1.7 feet per week – hasn’t stopped moving, but it isn’t gaining speed, an action that can indicate a landslide is growing more imminent.

Some 55 local, state, federal and Yakama tribal agencies are monitoring the slide, working to mitigate potential impacts and developing different response plans for a variety of scenarios. Those scenarios range from a slump that would see most of the landslide stopped at an inactive quarry on the south side of the ridge to a massive slide that closes Interstate 82 and dams the Yakima River. Authorities say the latter scenario is highly unlikely.

On Tuesday, rocks continued falling into the Anderson quarry at the base of the ridge, where experts say most of the 4 million cubic yards of rock and soil will land.

Most quarries receive some rockfall, Smilie said, but the Anderson quarry has seen a significant increase over the last few months. He said anywhere from a few cubic yards to 20 cubic yards of rocks have fallen, ranging in size from tennis to soccer balls.

Despite some rain and snow in the forecast for the next week, officials at the Yakima County Office of Emergency Management say the weather won’t have an impact on the landslide’s movement.

“The only thing affecting it is gravity,” Smilie said.

Meanwhile, emergency officials have turned over videos taken earlier this month to the Yakima County Sheriff’s Office for possible charges against a number of people seen scrambling around massive cracks that have opened up above the quarry.

If identified, the people could face $10,000 in fines and a year in jail for trespassing, said sheriff’s office chief criminal deputy Bob Udell.

Late Tuesday, a joint statement was issued by Gov. Jay Inslee and U.S. Rep. Dan Newhouse, who previously asked the governor to declare a state of emergency due to the potential danger posed by the slide.

Inslee’s office has declined to issue a declaration, saying it wasn’t warranted. But the statement said both Inslee’s and Newhouse’s offices were monitoring the situation and were prepared to take action.

“We spoke this week and are ready to mobilize the state and federal resources and proclamations necessary to assist impacted communities and infrastructure, in the moment they can be most impactful and responsive to the community,” the statement said.

“State and federal agencies are actively working with local authorities and the Yakama Nation to make sure we’re as prepared as possible.”