Survival Cache has a great article about the 7 types of gear you should have in your bug out bag. This is Part 4 to that series.
4. Shelter
If you are going to survive for 3 days you are going to need protection from the elements and a warm dry place to sleep. You need at least:
Some type of tent or tarp and a way to set it up
A ground tarp for underneath your shelter to stay dry or a sleeping pad (Never underestimate the importance of this)
Some type of Bedroll, preferably a good sleeping bag.
