Walk along the flood-sculpted western side of the precipitous Wallula Gap to the Mounds Pond Overlook. Geologist-author, Bruce Bjornstad, will point out ice-rafted erratics, spillover channels, and other features of the Ice Age Floods. This 4-5 mile hike will bring you to the 800-foot-tall cliffs of Columbia River basalt. Transportation and lunch are included.

Cost: $89.99 per person+tax