I think closer to the 'major' disaster areas (coast lines or barrier island) they would/might turn the gas off, since that would be a direct impact with the most devestating damage. I would figure the further away from the coast line you would be safer and still have gas as an option. Plus if you have a gas stove, you would be able to cook if the power was out for long spells.

I would use the natural gas generator if I was in the area that I knew the power would be out for long spells due to natural disasters. I am pretty sure there are kits to allow generators to run off of liquid propane as well. Well at least the larger, permanent generators for houses.