Shelter
A large plastic bag or space blanket makes a good emergency shelter. Even better, bring two or three; they also make good sleeping pads, sleeping bags and emergency ponchos.
Fire
Waterproof matches or a reliable lighter will help you get a flame started, but having emergency fire starters--balls of dryer lint, candle wax and cardboard, for example--will help you turn that flame into a real fire.
Water
A small, portable filter or chemical water treatment tablets will help you avoid the misery and weakness caused by water-borne illnesses such as Giardia.
Food
You can't pack a week's worth of food, but a fat- and calorie-rich candy bar might help keep you warm through a cold night or fuel your efforts toward building an emergency shelter.
First Aid
Think emergency first aid supplies useful in a crisis--a splint, triangle bandages, burn treatment packs and gauze, for example--not small bandage strips. Add an emergency whistle or mirror to help you summon help.
Building Supplies
Add Zip ties, duct tape, cordage and a sturdy knife, and you can build almost anything or repair gear that's been ripped, broken or otherwise damaged.
About The Author
Marie Mulrooney has written professionally since 2001. Her diverse background includes numerous outdoor pursuits, personal training and linguistics. She studied mathematics at the University of Alaska Anchorage and contributes regularly to such websites as eHow, Garden Guides, LiveSTRONG and Trails.com. Print publication credits include national magazines, poetry awards and long-lived columns about local outdoor adventures.