Two hunters ease their way South down the presently named Wood River Valley.  Further South and West the area joins the Malade River, now spelled Malad. The story goes like this: The French trappers with McKenzie in 1824 who were working the valley feasted on beaver tail which they considered a delicacy.  The tail is where the beaver stores it's reserves of fat.  The beaver on their menu had, in turn, feasted on Hemlock.  The poisonous plant had no effect on the beaver, but it had a bad,  bad effect on the company of trappers.  Because of the the sickness pervading the camp, the river was dubbed, "Riviere Malades" or "River of Sickness."  I know some writers credited the event to Alexander Ross or John Work, both of whom led expeditions through the area later.  Who knows?  Based on my studies, and the fact that I am Scot/Irish, I'm sticking with the McKenzie and the French Voyagers who would choose a French wording so...

All I know for sure is - there was a lot of misery in the trapper's camps for quite awhile.