January of 2011 I backpacked about 20 miles into Pike National Forest intending to stay the weekend. I left late Friday morning and was planning to be back Sunday afternoon. I had just received a Garmin eTrex 20 for Christmas and didn't bother taking any hard maps. Just the GPS. Well no one told me that alkaline batteries have an exponential discharge rate below 32 degrees fahrenheit... Well I must have left the GPS on overnight Saturday into Sunday because when I woke up to a blizzard a couple of hours before sunrise on Sunday morning the GPS was dead, and my tracks by sunrise were completely covered in snow.. Like everything else.. My sleeping bag, me, the inside of the tent, my outer layer of clothes, my backpack... I didn't even have snowshoes for the trek out. Just some microspikes... I ended up out there until Thursday. It was by far and away the most terrifying experience of my life. My only saving grace was my ability to make a fire with wood that was soaking wet, knowledge of basic survival shelters for added protection against the elements and reflecting a fire's heat.
I really honestly thought I was going to die in my sleep from hypothermia out there... That or carbon monoxide poisoning from trying to sleep so close to the punky fire all night.
What I learned...
Should be obvious.. Always bring hard maps.
......and don't rely on technology. Always have some primitive / low tech back ups.