Actually, falls are the number one killer in the outdoors. Falling is a potential hazard present in all environments and many, many people succumb to it. You can trip over your shoelaces and hit your head just wrong - and die. Any free fall, out of a tree or off a cliff, in excess of forty feet, and you are pretty much dead.

I knew I would draw heat in emphasizing the need for fire. The prime mantra in the survival school industry is "shelter is the #1 priority." Everyone knows it.

It is a little more subtle than that. Blasted by adverse weather, you need to create a microclimate that will allow body functions to regain something like normal function. Fire is handy in this situation.

In practice, you can't build a fire without some sort of shelter, but that shelter can be as subtle as the lee side of a boulder - not perfect, but it will suffice. You then create "shelter" by snugging up the hood on your very good parka (or better still, drag out that bivy sack you were smart enough to bring along). If you can't do that, you definitely need to build or find something sheltering.

Fire and shelter together solve the problem of creating a "recovery microenvironment," the vital necessity that will see you through to the next day.