Northeast slopes of Mount Rainier as viewed from Burroughs Mountain. Photo taken over benchmark at 7,830 feet elevation. Winthrop Glacier occupies the view, with Steamboat Prow to the left. Columbia Crest, Mount Rainier's highpoint (14,410 feet), is just under the cloud cap.
The summit lava cone is most clearly recognized from the northeast, where it floors the large Emmons and Winthrop Glaciers that slope smoothly up to Rainier's summit. Broad lobes on the glaciers' surfaces show the locations of the youngest lavas from Rainier's summit, now buried under hundreds of feet of ice. The summit itself is formed of two small overlapping craters, each about a quarter mile in diameter; the younger of these forms a nearly perfect circle of radially-outward-sloping lavas. The shallow floors of these craters are filled with snow and ice, but the raised rims are snow-free year-round because of high winds and because much of the ground is still hot. Steam or warm mist, at or just below boiling temperature, rises from the crater rims in many areas and has melted an intricate system of caves into the base of the crater-filling ice. On calm days, a faint odor of sulfur can also be smelled. The hot ground, steam, and sulfur smell, as well as the little-eroded shape of the summit craters attest to Rainier's recent activity.
The Winthrop Glacier is the second largest glacier on Mount Rainier, with an area of 3.5 square miles. It extends from the summit to the 4,700-feet level of the West Fork White River valley.