Thought I would comment on our experience with dehydration and related problems on our Carrizo Gorge Hike. I also, primarily for my own education, spent some time researching heat stroke, water dehydration, etc. as it relates to hiking in the desert.
In regards to the trip, we had a good strong group. Anything less and we could have had some serious consequences. I believe everyone was sufficiently skilled and strong enough to do everything that we did. All our problems were caused by insufficient water. If everyone had had another gallon of water each, I don't think we would have had any issues except for the normal blisters and sore muscles.
All of us have been reminded of the desert hikers number one rule -- nothing! is more important than water, we can do without food, shelter, etc. and last quite awhile, but being deprived of water for even half a day under those kinds of conditions can be deadly.
The way things developed, we were way out on the edge, there was little to no safety reserve left in the group. If we had experienced any further difficulties (making a wrong turn, snake bite, broken leg, or someone actually succumbing to heat stroke or having serious cramps while on the hike) things could have gotten very serious.
I think we all learned some lessons on this trip, each and everyone of us. The only benefit of going to the school of hard knocks, is to learn how to avoid similar situations in the future. Which is the main purpose of this email.
I didn't give the issue of water consumption as much thought as I should have, even though I had sent out an email suggesting to bring lots of water. More than we used at Bow Willow. What the heck! How much is lots? What kind of advice is that?
I had always heard the often repeated advice of one-gallon-per-day. So if a person used that as the criteria, we were gone from about 11am Saturday, to about 4pm Sunday. Lets see - that's about 29 hours. If the gallon a day rule works, we should have had enough with about 5 quarts. Not matter how you look at it, 5 quarts was not enough.
In researching a bit on the web, I found all kinds of inconsistent advice. So who is right? With our recent experience, we know that the one gallon a day rule wouldn't have provided enough hydration.
If you take the time to go through the links I've provided, I think you will agree that we were lucky this time. Think about it a bit, since two of our members are pilots: who would take off on a flight and only make a guess of how much fuel might be required? There are all kinds of variables that make that a complicated issue: head-wind, altitude, temperature, etc.. I think there are just as many variables while hiking. And when in the desert, the outcome could be just as deadly.
The one-gallon-a-day rule probably works OK if the temperature isn't over 85deg or so, and little to no exertion is being performed. So what about 95 to 105 deg F, coupled with very strenuous exercise. Some of these links say that because of water losses, that you need a quart of water per hour while exercising. A quart an hour, that's a lot of water to carry!
Out of the 29 hours we were out there, we probably were seriously exercising for about 5 hours on Saturday and 5 hours on Sunday, the remainder of the time we were at rest (or what passes for rest out there). That's a total of 10 hours, which equals 10 quarts; plus 19 hours at the one-gallon-a-day rate. If I can still add, that comes to about 3 quarts for the 19 easy hours giving a total demand of 3+10 = 13 quarts, or about 3.25 gallons.
I don't know what other people started with, but I started with 2.3 gallons. I did give some away, probably less than 0.5 gallon's worth. So I used about 1.9 gallons of water. And while I didn't suffer as much as others, I could have used more than what I started out with. I suspect, that I would have been fine with about 2.75 gallons.
At Bow Willow, I used about 1.75 gallons, and wasn't rationing myself. If I had taken my own advice for this hike, I should have had a lot more than 2.3 gallons I started with.
After all of this, I still don't know what the correct formula is. If you are interested, the following links might be helpful.
By the way, I did enjoy the hike and the company. It was a great group, who I would want with me anywhere. I'm glad I went. If you haven't looked at them yet, John's pictures are great.
One other thing, for those that haven't done very many backpacks before, either in the desert or in the High-sierras, this trip was harder than more than 80 or 90% of the hikes I usually go on. Usually we have real trails for more than 80% or more of the hike, and what cross-country is done, is in similar or easier terrain than we experienced on the Carrizo hike. And more importantly, the High-Sierras are cooler, and its quite unusual to be more than an hour or so away from good water.
Links about Heat Stroke
This last heat stroke link is really good about describing the problem, follow the links at end of each page, there are several sections to this. http://www.gorp.com/gorp/publishers/ics/hea_medb.htm
Some interesting, desert survival and water recommendation links: