Numero uno is lack of preparation, often because the typical lost hiker starts out his or her morning holding a cup of coffee in their kitchen and saying to themselves, "I think I'll go for a short walk in the woods today." You see, most of the people who end up in a survival situation are dayhikers, and they account for approximately 80% of lost hikers each year in North America.
If you trace back the elements that lead to people becoming lost and having to survive, the predicament often starts at home prior to leaving for their jaunt. They think that because it is a dayhike, nothing can go wrong, so they fail to do two critical things: Leave a travel plan with someone reliable, and carry the appropriate clothing and gear to deal with an unexpected emergency.
I've been there myself. Lulled into a false sense of security because "I'm only going on a walk in the field out back. No big deal. It's not far from the city. I've been hiking there before. It's near my house...and so on."
This Dayhiker Syndrome, as I call it, is where it all starts. It can be a deadly mindset to possess. Because you think it will only be a short stroll, you don't tell anyone where you are headed and when you will be back. Who will look notify search-and-rescue if you don't return? Where will they look?
With the Dayhiker Syndrome, most people who get lost are woefully unprepared to deal with making a shelter and fire, finding and purifying water, dealing with any medical issues, and having the ability to signal searchers.
Look, Mother Nature does not care if you have a Ph.D. in Outdoor Education, are an Aborigine, or write a survival column--if you don't play by her rules, you will suffer and probably die.
So, the next time you are sitting there on the couch, sipping that cup of Joe, and contemplating a morning stroll, remember to:
1. Leave a note indicating where you will park and hike. Also leave an approximate time of when you will return home, and then work out a response plan with your significant other/friend. For example, my wife and I have a two-hour window worked out. If I say that I will be back at 6 P.M. and then 8 P.M. rolls around without me returning, then she is my safety net back home who can make a call for help.
2. Carry enough gear to take care of the "Big 5" survival priorities: shelter, water, fire, medical, and signaling. I've outlined these in detail on other posts here so I won't rehash them, but you must be prepared with a daypack of quality survival gear to handle being stranded in the cold (or heat) for a minimum of 72 hours.