One cubic mile of ice

Mount Rainier's northeast side, seen from Noble Knob.

Rainier's glacial ice is estimated to be 4.2 cubic kilometers in total volume, or about a cubic mile of ice -- more than any other mountain in the lower 48 states. There are 26 major glaciers and many unnamed patches, covering about 34 square miles altogether -- more surface area than all other Cascade Range glaciers combined.

There are over 35 square miles of permanent ice and snow on Rainier. There are 26 major glaciers and many unnamed patches.

Emmons Glacier, the large one in this photo, has a 4.3 square mile surface area, larger than any other glacier in the lower 48 states. The White River flows from its terminus.

Carbon Glacier, visible in the lower right of this photo below the cliffs of Willis Wall, is the longest (5.7 miles), thickest (700 feet), largest in volume (0.2 cubic miles), and has the lowest terminus elevation (3,500 feet) of any glacier in the lower 48 states.

Fryingpan Glacier is visible on the left side of the photo, on Little Tahoma Peak. It is a smaller one, "only" 1.3 square miles and 2.9 billion cubic feet of ice.

Winthrop Glacier is visible in the center of the mountain in this photo, just to the right of Emmons, split off at Steamboat Prow. Winthrop Glacier: 3.5 square miles, 18.5 billion cubic feet.

Rainier is the tallest active volcano and the 5th tallest peak in the lower 48 states. It is "episodically active", meaning that although it is quiet now, it will erupt again. A giant eruption like Mt St Helens is not as much of a concern as are lahars -- large and fast moving mud flows. A small eruption or earthquake could trigger a lahar, with glacial melt, mud, and rocks (a kind of concrete slurry in a sense) flowing down the river valleys into populated areas and cities. Lahars in the prehistoric past have reached the present day cities of Puyallup, Auburn, and parts of Tacoma. There is a lahar warning system in place along parts of the Carbon River, with lahar sirens in the town of Orting and the city of Puyallup. There are also lahar evacuation route signs in the region.

Although the Cascade Range mountains are about 12 million years old, Mount Rainier sprang up in the midst of the Cascades just 500,000 years ago or so.

Many rivers begin on Rainier -- some emerging directly from ice caves at a glacier's foot. Major rivers include the Carbon, White, Cowlitz, Nisqually, and Puyallup.