Just to show how much more complicated this could be:
the last report is by his friends seeing him near the cables from Trail Camp. That is a long way, even with binoculars. People often wear clothing that, at a distance, looks the same.
We are depending here upon people who just came down from 14,000+ feet, and may still be affected by oxygen deprivation....which is a true description of their physiologic state.
In this paper, it is pointed out that red visual threshold is much more effected than blue. And personally, I think everyone's clothing looks black at 1/2 mile:
http://www.iovs.org/content/10/5/323.full.pdfKen is absolutely right about the possibility of miss-identification of the color of clothing.
Sorry to take off on a physiological journey here, but we are all waiting for news.
Here goes: The FAA suggests (not requires) that general aviation (non-pressurized) aircraft pilots use O2 at night above 5,000 ft (yes, only 5,000) because the retina begins to lose some color vision and depth perception. On a personal note: I was once at an 18,000 ft camp on the Mera Glacier, playing cards in the tent. One of the guys suddenly blurted out, "Hey, there are no red cards!" Indeed, everything looked a shade of gray. None of us had noticed this, even myself who knew about it. Ken's point is that lower oxygen pressure of altitude affects brains and perception in many ways, both the lost hiker, and his presumably normal group. This is not to be critical, it is what it is.
