Rowena Crest and the Tom McCall Preserve

At Rowena the old highway climbs out of the forest onto open grassland, then drops off the edge of the Rowena Plateau in a stack of hairpin loops. The crest stands nearly 700 feet over the river at the upstream end of the plateau, a promontory of Columbia River basalt that pushes into the channel and pinches the Gorge into the Rowena Gap. Toward the end of the last ice age the Missoula floods came down the Columbia again and again as a glacial dam in Montana failed and re-formed. Here the water jammed against the promontory, backed up into a temporary lake over The Dalles basin, and poured across the plateau, scouring it to bedrock and leaving ponds where whirlpools bored into the rock.

What the floods left is strange. The plateau is covered in low, evenly spaced humps of fine soil, called mima or biscuit mounds, and geologists still disagree about how they formed. The mounds in the middle of the viewpoint's roundabout are the one known exception: the Oregon Department of Transportation built them to match the rest.

The Nature Conservancy and Oregon State Parks look after the land as the Tom McCall Preserve, named for the governor whose conservation work helped protect the Gorge. A short, nearly level trail crosses the plateau past the flood ponds to the cliff edge; a steeper one climbs about a thousand feet in a mile and a half to Tom McCall Point and a view of Mount Hood. From March into May the grassland turns yellow with balsamroot and blue with lupine. The trail to Tom McCall Point closes from November through February; dogs are not allowed on either trail, and rattlesnakes are.