Update: This list has been updated here!
Ten items (or categories of items) have been determined to meet most critical survival needs in an emergency. This simple package of gear might mean the difference between comfort and misery in a crisis. Day walkers in completely familiar surroundings occasionally can do without a single one. Your error will be small should you carry all ten at any time you're on the trail.
Without a map and knowledge of how to use it, your adventure may turn into something less than enjoyable.
Used with knowhow, a compass makes that topographical map ten times as effective.
You may have to hike (or change that tire) on a moonless night.
At high altitude, the sun's radiation is more intense and your eyes can burn more easily. You won't know it's happening until the damage has already been done.
This is in ADDITION to the amounts you intend on using. Plan on half again as much water as you think you will need on the outing.
It gets cold out there at night. May include rain gear, wool shirt or sweater, head protection, mittens, extra socks, Mylar space blanket.
Candles, fuel tabs or other long-burning fire starter are essential when trying to start a fire with damp kindling.
To start the firestarter. Keep them in a waterproof match holder.
This is an essential tool! The Swiss Army knife is most popular.