Do you have a roof cargo box? Amazon has a number of automobile roof cargo bags that are quite reasonable (as low as $40). In a rush, you could throw that on the car and load it up. Does not require a roof rack.

http://www.amazon.com/s/ref=nb_sb_noss?url=search-alias%3Dautomotive&field-keywords=cargo+bag


You could also look at hitch-mounted cargo boxes. There are all kinds these days:

http://www.amazon.com/Rightline-Gear-100...words=cargo+bag


If I lived in wildfire country and had room in my garage or driveway, I'd also be looking at a teardrop or cargo trailer. You can buy them or build them:

http://www.tnttt.com/


I have a teardrop trailer for camping that would function for well for stuffing with cargo for evac.

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