Tidal lines on a hillside near Missoula

ID: 4715 ~ Source: Lake Roosevelt National Recreation Area, National Parks Service

This file appears in: Carving the Columbia: The Ice Age Floods

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: The Ice Age Floods

Carving the Columbia: The Ice Age Floods

By Charlie Byers

These gently sloping hills beside the lake show the marks of a tumultuous process at work. This region of the Columbia Basin was carved over eons by the meander of the river, by slow erosion, and by…