Excellent posts!

I'll just quickly expand a bit on hypothermia, things to remember. It's not a cold weather killer. It's simply your body not being able to produce heat faster than it's losing it. That's why most cases of hypothermia deaths are not in what most people consider cold weather. If you're out there alone, there is only one real symptom that you can recognize before it's too late to help yourself. After that you basically lose your mental ability to do anything productive. The symptom is uncontrollable shivering. When you get cold, your body naturally tries to make heat by shivering. You can consciously stop shivering if you're just really cold, but if you try to stop and can't, then it's time to stop whatever you're doing and get warm. You don't have much time. What comes next is that you're still cold and you stop shivering; that's when your body abandons the "make heat" mode and goes into "conserving heat" mode, trying to keep your body core warm. By this time, you won't be able to help yourself. People have been known to die from hypothermia with hot coffee still in a thermos.

General rule of thumb, once you start to really shiver and be cold, that's the time to stop and get warm. It only takes minutes to go from hard shivering to uncontrollable shivering to stop shivering. If you're not aware of truly how cold you feel, it can sneak up on you fast.

As pointed out earlier, backpackers are probably more prepared with gear than say hunters might be. I mean, shelter from the rain, ability to cook or make a fire, etc. are right in the pack. It's still not an excuse not to be aware though. Only takes a slip in a creek to get wet and the thought of, "I can make it to the next campsite, it's not that far away..." to get into trouble.