View the actual ice dam location at the Amber Bear Inn.  There are viewpoints unique to this property that allow you to view this prehistoric landmark from end to end, a distance of over 20 miles!

Until about 12,000 years ago, many of the valleys of present day western Montana lay submerged beneath a lake nearly 2,000 feet deep.   When the Cordilleran Ice Sheet dammed the Clark Fork River near the present day location of the Amber Bear Inn, the result was Glacial Lake Missoula.  The water behind the glacial dam created conditions causing it to weaken until it burst through in a flood of Biblical proportions from Montana across Idaho, then Washington and finally Oregon before flowing into the Pacific Ocean.

There has been a mystery concerning the topsoil of the fertile Willamette Valley region in northwest Oregon being hundreds of feet deep.  It was determined to be originally from the topsoil of the prehistoric jungles of eastern Washington.  Raging water and chunks of ice ripped away flatland and mountainsides alike, resulting in massive ripple marks and creating the rocky scablands across eastern Washington before slicing through the Columbia River Gorge changing it forever.

One theory is that over the course of centuries, Glacial Lake Missoula filled and emptied in repeated cycles.  Another theory is the dam broke in its center, flooded to the Pacific, with the shoulder ice locking the Clark Fork River to repeat the fill/flood process in a much shorter timeframe.  The ultimate consequence is a mystery embedded in the land.

Flood Facts:

• The ice dam was in excess of 2000 feet high.
• The narrowest point of the ice dam was over two miles wide.
• Prehistoric Lake Missoula was as big as both Lakes Erie and Ontario, nearly 20,000 square miles!
• Estimates compare the flood water force to 60 Amazon Rivers. The Amazon is by far the largest river in the world.  
• Van-sized boulders embedded in ice floated over 500 miles; they can still be seen as you travel the Lake Missoula floodpath!