Almost deep enough for Hells Canyon, but not that canyon from Hat Point on the Oregon Side. It takes a bit of endurance to drive up to Hat Point, but Horace did it ca. 1948. There's little or no evidence that he visited the Idaho side of the our deepest canyon. I think this is more likely near Hells Canyon than above the canyon itself - an Oregon tributary to the Snake River. (Click to Enlarge)
