This is an accompanying poster for classroom use from the stunning program Ice Age Flood.

Spectacular floods radically changed the landscape of the Pacific Northwest some 17,000 years ago when ice age glacial dams near Missoula, Montana broke apart and unleashed an inland sea. Geologists believe this powerful flood was the greatest moving body of water in the Earth’s history. This award winning program helps students understand how geography can provide clues to the distant geologic history of an area.