I combined this trip with Cowiche Canyon for a long day. I should probably have done them in reverse order, visiting Selah Butte in the morning to increase chances of avoiding the winds that likely increase in the afternoon. It was partly cloudy, which made for occasional interesting light draping itself across the hills, and dropped the temperature quite a bit.
The road to Selah, as per other trip reports, is pretty gnarly. The gravel washboard isn't bad compared to the couple miles of rutted, rocky, undulating nastiness that follows. Not recommended for low-clearance vehicles. You can park by the lower gate and avoid most of it, walking up the road past flowers and horned larks and such, but I had the big truck and so drove to the upper "parking area", a wheel-rutted garden of Hookers balsamroot. A very nice man and his son were going to target shoot (it's BLM land, so don't grouse) but decided to drop down to practice so I didn't get that Beirut feeling as I was returning over the ridge.
While this hike gets advertised for its flowers, it is the grand views of prehistoric landforms that I found really magnificent. Walking along the edge of the ridge (there are no trails, really) gives sweeping views of the massive uplift at the south end of the Yakima Canyon. Big oxbows in the river canyon tell of the force of floods for tens of thousands of years, probably. If you stand still long enough, the land appears to flow before your eyes and you start to see the swirl of big water in your mind's eye.
Of course, there is the mark of man here: the barbed wire you crawl through that keeps the cows on one side and the lupine blooming on the other, the dam on the Yakima far below, the canyon road with trucks and cars. But the land overwhelms and makes us look really, really small here.
I walked north as recommended by "Desert Hikes", but in order to stay close to the river, I dropped down a game trail through a gully and sidehilled a slope to the viewpoint. You have options here depending on your comfort level and shoes (some ankle support recommended for slopes- I had good traction, but was in approach shoes with low ankles and wished for my day hikers).
A splash of bright pink caught my eye on the ridge and I found a hedgehog cactus beginning to bloom. Just one, though there are small cacti throughout. I alarmed a pair of swallows near a rock outcropping where they may have been nesting, and they buzzed me with surprising force, swooping in tight angry circles and creating amazing wind rush for such teeny birds. Since no one was there, I could do my St. Francis bit and assure them aloud I wasn't a nest-maurading raven as I scurried away over the rocks.
On the drive back through Yakima Canyon, I saw bighorn sheep leaping along the western cliff face in the usual place (there is a wide shoulder and a couple pullouts in the northbound lane, right as you enter the canyon- look left across the river). Stopped to see these phenomenal athletes with their ballet moves on the type of rocky terrain I had been stumbling on not too long before. Yakima Canyon is lovely now with its brief cloak of green, and especially in the late afternoon light- fishermen on the river, rafters in the campgrounds having dinner, and all is good with the world.