Here is what Charles Houston MD has to say about HAPE on p. 144 of in his latest (fifth, 2005) edition of Going Higher: Oxygen, Man, and Mountains (available from Amazon):
"Because it is difficult to determine the number of people at risk, we can only approximate the percentage of visitors to mountain areas who develop HAPE. In addition to altitude, there are many other contributing factors, such as speed and method of ascent, level of exercise, and individual susceptibility. Extensive data collected from Mount Kenya, the Mount Everest region, the Indian Himalayas, Peru, Colorado, and the European Alps suggest that anywhere from 0.01 percent to 4.5 percent of the people who go to high altitude develop HAPE. One report from the Sino-Indian war in 1962 gave an incidence of 15 percent. Most cases occur after twenty-four to forty-eight hours at altitude, mainly above 10,000 feet. These disparate findings illustrate the difficulty in interpreting information collected in different ways by different individuals in different situations."
What might this mean for Mt. Whitney? Taking 160 people per day during the summer as a working number (60 overnight + 100 day):
* 0.01% is about one every other month
* 4.5% is about seven per day
* 15% is 24 per day
I have long suspected that unrecognized cases of HAPE (incipient, perhaps) among Mt. Whitney visitors are more frequent than commonly thought. For any number of reasons the afflicted person may turn around and descend, thereby quickly and easily correcting the situation--without ever having been aware of what it was.
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And AMS? Houston quotes a number of prior studies. Extracting results that are most meaningful for us, the instances of AMS, in previously unacclimatized people, were (ibid p. 113):
* 40% of those going to 8900' (1989)
* 27% of those going over 9000' (1993)
* 17% of those going to 9500' (1985)
* 42% of those going to 9800' (1990)
* 34% of those going to 12000' (1989)
* 42% of those going to 14000' (1986)
As we all already well know, AMS strikes a large fraction of Whitney visitors. But here are some quantifications. The unacclimatized should learn that AMS is possible--even likely--and know how to prepare in advance for it. And how to deal with it if it hits. Use the search function to find the voluminous information already posted about it on whitneyportalstore.com.
I don't have analogous frequency numbers for HACE. But HACE--the "end stage" or severe AMS--is considerably less common than AMS or HAPE. Nevertheless, the new Mt. Whitney visitor should probably learn a little about it, as well.
