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Have you ever heard of a mountain growing right before your eyes? That's what happened on October, 28, 1983, when Borah Peak, the highest mountain in Idaho, grew about eight inches higher in two minutes. Around the same time, the valley floor along 26 miles of the Lost River Range suddenly lowered 10 feet. Can you guess how this happened?
It was an earthquake that caused these drastic changes. Idaho is a state of dramatic geographic contrasts. It is a geologically active region that includes glaciers, volcanoes and earthquakes, all of which have produced a spectacular but harsh landscape.
Glaciers move very slowly and grind away at mountains. The Otto Glacier is the only remaining glacier in Idaho. Only a small remnant of what it used to be exists on the north slope of Borah Peak. It and other glaciers have created more than 500 cirques (French for "circle") in the high mountains of Idaho. A cirque is formed when glacial erosion removes big blocks of rock from mountains, resulting in a circle surrounded by mountains. Shallow cirques appear as wet meadows today, while the deeper ones with bowl-shaped floors may contain lakes.