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Disasters and Accidents
00000179-65ef-d8e2-a9ff-f5ef8dd70000In early October 2017, large cracks were spotted on the ground at Rattlesnake Ridge, a hillside about three miles south of Yakima, Washington. By January, the cracks had widened and emergency officials became concerned that a major landslide could imminent.Around 50 residents who lived on a small tract of land at the bottom of the hillside were evacuated and officials prepared for the worst.By the end of the month, geologists and engineers concluded that the landslide was a slow moving one and the risk of a major, catastrophic slide was low. Warning signs were taken down and residents were allowed to return to their homes.

New Report Says Massive, Sudden Landslide At Rattlesnake Ridge Unlikely

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Washington DNR - tinyurl.com/y843yqol
Geologists now say that the risk of a rapid, massive landslide on Rattlesnake Ridge is remote.

The landslide on Rattlesnake Ridge near Yakima, Washington, is likely going to be a slow one—it could take years or decades to fully come down. That’s the upshot of a new independent geology report commissioned by the state.

The report by engineering consultants Wyllie & Norrish Rock Engineers said the incident is “predictable and manageable” with all the eyes and equipment monitoring it.

They also say there’s an 85 percent chance that it’s going to be slow moving and a 5 percent chance it could be rapid. If the slide were to start moving more quickly, the state’s current monitoring would detect that.

The report predicts that material will likely continually fall into the adjacent quarry and the nearby county road. But there is a slim chance that the landslide would reach Interstate 82 or the Yakima River.

The firm recommended that officials set up a sensing system that would alert them by cell phone around the clock if the slide moves.

Yakima County Office of Emergency Management held its last scheduled press conference this week and said emergency management activities are ramping down.

There isn’t word yet if the residents affected by the landslide will be able to return to their homes, but the county managers said they are looking at that.

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Credit Wyllie & Norrish Rock Engineers - tinyurl.com/y8zbskcm
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Wyllie & Norrish Rock Engineers - tinyurl.com/y8zbskcm