The action of glaciers on the comparatively soft material of Rainier’s cone results in rapid disintegration of the rock; and the river is milky with rock flour.
The forest becomes more dense, as the highway follows the western slope of Mount Rainier between the valley and summit. Douglas fir and western hemlock, the dominant species in this humid area, attain a thickness of from 4 to 8 feet at the base and tower to more than 200 feet in height. At higher levels the lodgepole pine and species of fir mingle with the Douglas fir and hemlock. Lower down are found many red cedar and white fir.
The historic old trail over Naches Pass, to the north, was used by the Puget Sound and Plains Native Americans. The inland Klickitat, riding this narrow trail on their hardy ponies, would visit their tribes on Puget Sound and feast on first-run salmon and clams. In early fall the Puyallup, Nisqually, and other Sound tribes, mostly afoot, would come to the higher altitudes to gather huckleberries, seeds, and nuts. Later, this same trail was used by horse brigades of Hudson’s Bay Company, carrying supplies to interior posts.
The Longmires, Ezra Meeker, and other pioneers left the Oregon Trail at The Dalles and turned northward through the Yakima Valley to Puget Sound. Vestiges remain of the narrow road cut by these pioneers up the eastern slope of the divide.