Another hiker on the trail emailed me to say that he was quite sick before he fell. Possibly even threw up just before. The thinking is that in his weakened, dizzy and maybe disoriented state, he mis-stepped, or misjudged the edge, and fell over the edge. The spot, if I understand correctly, was maybe a hundred yards before the base of Mt Muir (closer to the MMWT/JMT junction).
I am sure we all offer our condolences to the Kato family.
