We lived on the California central coast for 25 years, with the possibility of earthquake, wild fire, Diablo Nuclear Power Plant incident (five miles distant), dam burst (six miles inland) and tsunami (we had two warnings during that time, related to off-shore earthquakes; couldn't help but think of Half Moon Bay, California some years back).

Suffice to say, a well thought-out evacuation plan was prudent, backed with sufficient gear/food/water to bridge the potential gap between event and relocation to suitable accommodations outside the area (an aside: over the years, there were any number of estimates suggesting that as little as ten percent of the area population had effective plans/preparations in place).

Besides having a couple of week's supply of water/food set aside in single storage at home (intended more for bug-in), I also maintained a separate, smaller 3-day supply of food/water ready-to-go — no time required to sort, assemble, and pack in the event of a hurried evacuation. Of course, if time permitted, we still had the option to grab additional food/water from the main supply.

The included food was selected based on: expiration dates, packaging bulk, weight, water required to prepare, ease of preparation, appeal to our taste buds (both wife and I had to like it), and nutritional value. Things like Lipton Pasta Sides, Albacore/tuna in foil pouches, soups/stews requiring no water/heated right out of the can (though, this supply, we try to keep canned goods at a minimum, due to weight). I've discovered lots of food products that we regularly eat come in alternate packaging that I might not buy for daily home use, but prove to be ideal for an evacuation kit. You've probably seen the precooked, no refrigeration required bacon on the grocery shelves (haven't brought myself to look at the preservatives used). I guess benefits can be derived from our migration to the fix-it/eat-it-on-the-run society.

These days, in light of the Katrina experience, I've bumped that 3-day supply up to 7 days, despite the fact that we live in an area with fewer potential disasters.
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"Things that have never happened before happen all the time." — Scott Sagan, The Limits of Safety