The Ice Age was about 12,000 years ago. Not long in geologic time.

Idaho looked much different than it does today. You could say Idaho was really cool. Frozen rivers of ice, called glaciers, inched their way down mountains and valleys.

The glaciers were powerful. They ground and carved everything in their way. They moved house-sized boulders, widened river valleys and, sometimes, created pockets along high mountain ridges. When the climate warmed up, those pockets filled with melted glacier water and created high alpine lakes, like the one in the panorama.