Two Sisters Butte at Wallula Gap
Sisters Butte from the parking lot
This is a rock formation in a geologically interesting area. The surroundings gave me a beautiful feeling of being surrounded by Buttes and Mesas in the green of a mild winter. Wallula Gap is a spectacular water gap, a place where a river flows through a pass in a ridge. Thirteen thousand years ago the largest floods in the history of the world had to come through this gap because on the West was the Cascade mountains, on the east was the Rocky Mountains, and on the south the Horse Heaven hills was a blockade as they ran all the way over to the Blue Mountains. So the Wallula Gap was where everything came through to the Columbia to run out to the ocean. 40 to 100 times the state of Montana filled up with 500 cubic miles of water. When an ice dam melted the water came crashing through the gap at 40 miles per hour and 18 cubic miles per hour. The Gap was not big enough to allow all that water to flow through so water backed up into the Pasco Basin, up the Yakima Valley to Yakima, and up the Snake River to the mouth of the Salmon River. The area was scoured by waters that overflowed the tops of the gap somewhat. This left the most solid of the ancient lava flows as Buttes (small atrusions) and mesas (more large round flat topped structures).
From Spokane take I90 to Ritzville, then 395 to Pasco, then follow signs to Walla Walla on Hwy 12 just before Pasco. Stay on 12 for about 20 miles and take the right to US 730. After this juncture it is exactly 1.7 miles to a parking area on your left just under the main rock formation. Climb the fence ladder and take the trail up to the top and between the two buttes. The view from here is great on all sides. You can then walk away from the highway into sand dunes, just don't cross the fence into the northeast farm. Southeast you can cross the fence and road and climb up into the other dark cliffs if you want some further challenge.
Take care near the top of the climb to the area between the bases of the 2 buttes. The rock is all very loose. Go very slow and be sure of each step.