Apparently, they could easily follow his foot prints in the snow, but then he decended into cliffs and rocky areas with no good snowy foot prints.
So the searchers had to closs the full creek to check the other side...this is where they were getting wet and cold.
I do not think that they know if he fell in.
But this is why the need the Eugene water rescue team who is better equipped to cross cold water.
How big is this river!