Tidal lines on a hillside near Missoula
This file appears in: Carving the Columbia
Look closely at the hillside in this photo, and you can see lines carved by waves. This canyon near modern-day Missoula, Montana was once the shore of a lake that covered hundreds of miles.
This file appears in: Carving the Columbia
Carving the Columbia
Between 18,000 and 13,000 years ago, glaciers advanced and retreated over northern Washington. This ice formed a fragile dam on the Clark Fork River, which slowly filled with water, creating glacial Lake Missoula. The lake spanned hundreds of miles…