Last summer Hurricane Irene hit and although we didn't need to evacuate, we were without power for 3 days. Add to that the joy of getting discharged from the hospital the afternoon before it hit and you can imagine that I was ALMOST caught flat. Fortunately I have a "go bag" and checklist just in case.
One thing to keep in mind is that most things PWD use have expiration dates, i.e.: insulin, infusion sets, test strips, batteries, etc. Always rotate your supplies. For example, when you get a new supply of insulin put it in the back of the refrigerator and use the oldest (unexpired!) vial first. When that is used up, use the next oldest next and so on.
In my "go bag" I have 2 bottles of glucose tabs, a box of syringes (I pump but I have those "just in case") and a checklist of "expiration date items" - insulin, glucagon, infusion sets, pump reservoirs, test strips, Ketostix and spare batteries for both my glucose monitor and my insulin pump. I list appropriate quantities to last 21 days since that is as long as I could possibly expect to have to gut it out before sufficient stocks of medical supplies would be able to be brought in after a natural disaster. Added to the bag are a notebook and pencil to keep my BG log up to date as well as a flashlight and all other prescription & first aid items. One thing that helps is that I keep all of this stuff (except the insulin) in one place and not scattered around. Also in the bag is a copy of my health care directive, emergency contacts list and an abridged personal medical history.