Long time lurker, new member on the forums!!! I love all the great info I have recieved from the forum members, a sincere thanks to all those who contribute....

So back to the question at hand.

The best advice I can give, to add to what has already been posted, is that when hiking/camping/climbing/etc. one of the simplest things to do/remember is to assign everyone a "buddy". The military refers to this as a "battle buddy", I can't remember what we called it in the boyscouts, and at the PD we call it a "back/partner". It is an essential safety measure.

Essentially you divide the hiking/camping/etc. group up into pairs, if there is an odd number, assign 3 to one group.

These "buddies" should get to know eachother a little bit before embarking on the journey. Introduce yourself, discuss what equipment you are carrying, your experience, any relevant medical history/conditions and/or medications that you must take (diabetic/asthmatic/etc.) and where those emergency medications are kept on your person/pack. Although friends and family members will likely pair up themselves, this is a good way to get to know a new person.

When venturing off on the trail, going to the restroom, beginning a new hike after a night in camp, etc. It is each person's duty to inform their "buddy" where they are going and when they will return. If the pair ventures off together, they should notify someone in another "pair" that they are breaking away from the group for "x" reason and will return in "x" time. This helps to avoid the "group-think" mentality that so often happens where everyone just assumes that someone else knows where they are, what they are doing, and will call for help if they are missing.

This is great advice for any weather conditon, and can mean the difference between life and death in extream (hot/cold) environments. I also recommend using the "buddy system" when on a school trip, day-care outing, etc.

Had this "buddy system" been in place during your example above, that person would never have been "left behind" by the group.

Best of luck and keep on enjoying the great outdoors.

-Silent