Once upon a time, long, long ago, there was a lake. A large and deep lake, formed by an enormous glacier that crept down from the north and blocked an entire drainage of the Rocky Mountains. Periodically, the glacial dam would break up, triggering enormous floods of water rushing toward the Pacific Ocean. Then the dam would build again.
Its waters flooded the valleys of western Montana. Five hundred cubic miles of water over 3,000 square miles of land. Glacial Lake Missoula filled and drained some 40 times over a period of 2,000 years.
Just as the waters shaped the land, the land shaped us.
The Kootenai River to the north, the three forks of the Flathead River and Flathead Lake, where the flow pauses on its way south, the Bitterroot, the Big Blackfoot and finally the Clark Fork, where most of the water meets and flows west toward the ocean.
Native people recognized the fertile valleys of the Kootenai, the Bitterroot and the Flathead for their abundance of plants and animals that sustained life. White explorers, following old Indian trails, used the river corridors of the Blackfoot and the Clark Fork to find their way through the landscape.
From the Tobacco Plains where explorer David Thompson established a lively trade with the Kutenai Indians who had lived there for centuries, to the southern end of the Bitterroot Valley where the Lewis and Clark Expedition fortunately came upon a camp of 400 Salish Indians who shared food, supplies and local knowledge with the haggard explorers, the corridors of the big rivers still guide our way through western Montana.