This was a major turning point in the journey of the Corps
of Discovery. After Clark returned to Lewis, and discussed the river
they decided to abandon the Salmon and the Corps proceeded up the North Fork
on foot and horseback.
The Salmon River simply had too many whitewater rapids for
them to traverse through safely on their canoes. But this moment signaled a
sever decline in the comfort level of the troups. They had hundreds of miles
of rugged mountain travel in front of them - through the rapidly approaching
winter weather.
Heading up from the Salmon River, towards what is now the
Idaho/Montana border, and high pass over the Continental Divide, the Corps
of Discovery lost the trail! Hence
the name of this mountainous divide, "Lost Trail Pass." Clark's aborted journey down the Salmon
River was the only time they had to turn around on their expedition.