Yah, as an example, I carry a 2500cu in pack every day which is really geared at getting me home. With the various supplies and a bit of clothing it is full. I don't carry much (if any) food in it and do not carry water in it, although my target is to add 4L of water for my dog and I from my office or car supply if in a disaster. So that is about as much as fits in 2500cu in. Consider it a 24hr pack.

I figure this is a good baseline to build on where you factor in food, water and additional clothing.

Part of the question is also, do you plan on walking for seven days, or do you have a brief walk to some shelter. Or are you planning on driving and just have the pack for convience and just-in-case?

What I'm trying to get at is -- you need to pack to a target that is realistic for you to carry for your target distance.

Personally, I think I'd be happy with about a 4500 cu in pack for longer term situations, but I doubt I'd pack much more than I have in my 24 hr kit other than more water and food. The gotcha is water is darn heavy...

Another consideration is how much clothing are you planning on carrying. Clothing, while light, can be bulky and take up a lot of room. In the midwest, I suspect it would make a huge difference in the winter vs summer for example.

One thing you might want to do is put everything together in a pile that you think you are going to carry and then eyeball the size before you go pack hunting.

Which comes to another point in picking a pack. When the load gets more serious, you really want a pack with real support. I would read backpacking reviews of the packs you are considering and make sure they perform well with heavier loads. Most book backs and military style packs don't have much if any support. I use a book bag style but the load is fairly light.

-john


BTW, here are some (old) pictures of my 24 hr kit. I'm re-doing it and hopefully will have revised pictures at some point. Note that some of my items are fairly specific to my situation and I would assume yours would look slightly different.