Even as volcanic forces were building up this land, the slow, inevitable power of glacial ice began to shape and form it. Glaciers come from snow that does not melt from year to year-it accumulates to greater and greater depths. The weight of the snow presses the air out, packs it tight, and compresses it into ice. Gravity pulls the ice down the mountainside, both scouring and smoothing the bedrock as it goes. Freezing and thawing break rocks from the adjacent stones, and they fall onto the glacier's surface.
More debris is picked up by the passing ice.
This is an inexorable process that continues today and will alter the mountain in the tomorrows to come. Nisqually Glacier is one of the most accessible glaciers on Mount Rainier. It can be viewed readily from Nisqually and Glacier Vistas located less than 1-mile from Paradise visitor facilities. Nisqually Glacier advanced and retreated three times between 1965 and 1992. The most recent period of retreat occurred between 1985 and 1991 during which time the glacier thinned by 52 feet in the region immediately west of Glacier Vista.