A 20-acre slab of Rattlesnake Ridge continues its downward slide near Union Gap, but at a significantly slower rate, officials say.

An adjunct geology professor at Washington State University said the slide is likely to grind to a halt long before it ever hits Interstate 82 or the Yakima River.

Stephen Reidel.
Reidel

Stephen Reidel, a research professor of geology at WSU’s Tri-Cities campus, said rocks from the slide falling into the nearby Columbia Asphalt quarry are likely to form a buttress that will stop the slide in its tracks.

“If you just take a look at it, the rocks fall down the hill to the quarry,” Reidel said. “It is as far as it is going.”

State and county officials, as well as scientists, have been monitoring the slide since October 2017, when a crack was first spotted in the ridge near Union Gap.

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Yakima Herald