Sadly, several months ago a similar incident in the Florida Everglades made the news. Small group of Boy Scouts were hiking from US 41 towards State Road 84/I-75 IIRC. Here in Florida the combination of heat and high humidity will often have heat indexes in the triple digits.

When you're walking in the swampy water on a 85 to 90F day, you really need to be aware of your increased need for water intake, BIG sunshade type hats as well as sunscreen etc.

It becomes a bit of a catch 22 situation, most sunscreens and bug sprays hinder your ability to easily sweat which is needed for heat relief, the high humidity hinders the ability of the sweat to evaporate and the high heat just makes life miserable and degrades your decision making abilities.

It would appear that all of these as well as some planning and preparation issues played a part in this local tragedy.

Sad and for the most part preventable.

Very sad story but it's not just the heat to keep an eye out, humidty also has to be watched. Where I live 70's-80's are average temps but this last week the humidty was very high, my son was showing signs dehydration. Key is water, water, water.

my heart go's out to everyone involved.on my first drive thru the SW a few years ago i did a post from a motel computer to the effect that from a Minnesota's point of view why i see so many posts here on the subject of water storage.some places there just is none. even from the cool inside of my car the desert was more of a worry than a drive thru northern Canada at 30 below.

Its very true and very scary how quick heat can hit you, even when trying to stay hydrated. I used to be active in a medevil re-creation group (SCA) here in Florida. Wearing about 50lbs in metal and hardened leather armour was my norm...
One event when it was in the high 90's, pretty much anytime April thru September, I came down with heat exhaustion. We have water bearers who keep the guys as hydrated as possible, squirting water into our mouth via a sprayer and also will shoot water on us (usually the chest/neck area). It was a long list, and a brutal one, no elimination just keep fighting rotating between 6 rings. Fight until you're killed, get back in line, repeat.
I was being careful to drink whenever given the opportunity, until my belly felt full. I knew by the time I hit the pits I would sweat/absorb enough to not be bloated. Well, after about 2 hours into this three hour grind it hit me. Just standing there waiting when all of a sudden I felt this wave of heat roll out from my padded jacket, up into my helmet. I instantly felt my knees go weak and felt sick to my stomach. I dropped my sword and shield on the spot. Started walking slowly and carefully to a table that was about 25' feet away removing my helmet and just letting it hit the ground. Called a water bearer over. Yelled for a chirurgeon (first aid responder) because being one myself I knew how bad this was.
I went through 3 gallons of water, drinking between a 1/4 and 1/3 of it. The rest was drooled down my chest, sprayed over my back (as soon as I was stripped from my padded jacket and armoured belt),my head my armpits and my crotch. I also had 2 quarts of gatoraid fetched from my camp (for the electrolyte replacement). All in all it took about 45 miniutes of doing NOTHING but sitting in the shade, drinking to rehydrate, being doused in water and having three fair maidens (god bless them) fan me to get back to normal. A very weak and ehausted normal, but out of the danger zone.

Often in hot conditions I find that carrying the water required is a burden. But it is better to be burdened and alive than the other alternative. A short hike with more water is much better than a longer hike where I run out of water and become dehydrated. This causes a loose of the endurance first. That same endurance I require to finish the hike.

In short carry enough water or as above turn around when you have used half up.

True - however, unless you're strong and in shape you will struggle carrying something like 30-40lbs of water in scorching heat. More exertion means more sweating, hence wasting precious body fluids. Getting a suitable container and/or a backpack large enough to accomodate it might be a problem even if you have plenty of water available.

Also, drinking enough water could be physically difficult if not impossible. FM 21-76 says a person doing hard work in 43°C requires 19 liters of water per day. That's a lot. Drinking like 1-2 quarts of water per hour to prevent dehydration is likely to upset the stomach after a while. Again a bad thing to happen when you're close to dehydration already.

In my own modest experience, the only solution in the desert is to limit hard physical activity to the cooler hours of the day - dusk, night, morning. During midday your only option is to stay still in shade if you want to last more than a couple of days.

You neatly covered yourself Tom but the caveat of 'unless you're strong..."No offense but sometimes you have no choice but to carry all that water. I went on a canyon hike today and 12lbs of my 29lb pack was water. For a 3 hour hike. Of course I had the choice of going out or not and there was zero water in the desert for me. And no I did not drink 1.5 gallons in that time frame but I could have.

Military operations are a separate issue, you have no choice but to go out when your told. I have BTDT, and carried a 100lb ruck with 45lbs of water, 40lbs of ammo and 15lbs of whatever else fit. Not including what was carried on me.

I know that the Armed Forces as a whole are now taking a much stronger stance on water intake and heat injury but its still the individuals job to 'hydrate'.

Suffering is easier than carrying the water, but so is death by dehydration, no real effort is required for that either.

The option of closing all public trails during the day in Arizona when it gets hot would smack of Government Interference. Or saying you can only go if "you're strong" would certainly get them quickly into court.

The only solution is education and practical guidelines that the those who wish to can follow.