I've been watching the news about the gas explosion in San Bruno. Admitably it was a one in a million incident, but another similar story appeared in the news the day before in LA somewhere if I remember right. I don't believe that I know anyone who lives there, but it did get me thinking.
If you have all of your preps at home and something cataclysmic happens to your home, you are SOL. Even if you were in a house that survived the original blast yours is going up in minutes from the fire if you were next to it. That doesn't give you much time to get your gear out. So, it seems to me that an off-site storage point for your essentials may be prudent.
My thoughts: A safety deposit box, small storage space at a storage rental place, someones (Relative) house out of the area.
Things to store as back ups:
Hard Drive backup
Clothing for each family member
Of course you can add more to these, and please post them here (I might learn something) but you get the idea. Off site storage of critical items that you will need immediately.