A so far slow moving slope failure has developed just south of Yakima where the Yakima River cuts through Rattlesnake Ridge at Union Gap. I have had numerous emails and linked facebook posts sent my way on this.
This failure is a worrisome event. The orientation and geometry of the fractures suggests that the movement is towards the steep slope of the gap; however, news articles suggest that mush of the slide will be directed towards the quarry. The cracks have formed a graben-like feature. One of the articles by the Yakima Herald noted rock fall onto Thorpe Road. That suggests some deformation may be taking place on the slope below the fractures and on the steep slope.
Maybe a bit more on this later. Travel and now work precludes much time to get into more detailed theory or research or information sharing.