Warning: Dimple Rock Dangerously Undercut

posted October 30, 2000
by Jason Robertson

I went down to Dimple Rock on the Yough This morning with Ohiopyle State Park manager Doug Hoehn and s group of rangers, outfitters, and guides. The dam had shut the river back as much as possible, and it was reading .7'. The water was very clear, and the morning sun was shining down under the rock from upstream. From the river left shore we were able to wade out and probe under the rock with a long pole. Then we looked underneath the rock with a divers mask.

What a sight! Dimple Rock is sitting on a rock outcropping. It overhangs the upstream edge by four to six feet over much of its width. It tops out an irregular "room" roughly four feet high. The water was clear and appeared calm. Even at this low level, the roof of the "room" is a foot below the surface of the river. At 3.5 feet, when the Dimple Rock pillow starts to wash onto the top of Dimple Rock, the "roof" of the "room" will be under roughly 7' of water. The room is so large that the trees removed in the 1996 drowning almost certainly did not fill it. The water was quite murky at that time, which is why no one got a clear view of this area.

My theory is that most rafters who flip above the rock stay in the pillow and are washed to the right and safety. A few unfortunate folks get washed deep, and end up under the rock. They are unable to work their way out the sides and back to the surface before running out of air, but are eventually washed free. This has happened 3 times over the past decade.

So now we know. Dimple Rock is VERY undercut! Doug Hoehn has pulled together an advisory committee to look into safety on the Yough, and Dimple Rock in particular. If you have any comments you may email me at ccwalbridge@cs.com.

Charlie Walbridge, AW Safety Committee

Associated Rivers

Youghiogheny [PA]
6. Lower III