On my last trip (June 3-4) we to two different hikers that had lost the trail between Trail Camp and Outpost Camp. I thought that it was due to the snow, but if this hiker got lost in the same area, it doesn't seem that snow could be to blame anymore.
Late in the day, the pound down the switchers and ledges from the "last foxtail" to Mirror Lake has claimed (and hidden) its victims. That's where I would concentrate this search.
