concrete tents with inside painted or coated in hard wax combined with with layer of dust to lessen the stink wax can absorb. even regular canvas and concrete mix or lime and diy mix.
shipping container houses anchored down if you need to dig a hole in solid rock maybe try something like a pressure washer with abrasive for makeshift waterjet cutter.
might be a good idea higher up like on side of mountain. maybe turn some shipping containers into fish farms and take lots of potato’s and lawnseed. anchor them down good.
gondola might be good option if no roads can access.
rabbits and chickens breed / grow fast.
things to pick for
flooded vending machines since they are no good anymore because food wont be able to be stored in them after flood, get some of the wet cash. or repurpose the machine itself and turn it into arduino or prize vending machine.
shipping containers with things in them like , chainsaws , boats, boat motors, toilettes, doors, arduino stuff, stepper motors, windows , mirrors, lumber/drywall, plasma cutter welder units, pressure washers, hotplates , microwaves, solar pannels, solar pumps, batteries, forklift batteries, fiberoptic cable, electric wire etc… that will be swept away from if dam collapses. maybe take plasma cutter if they are locked. maybe use large hellicopters to reach them(sky cranes).
priceless books and art
wind / waterproof cloathing – nylon , gortex , rubber
old windows and doors from buildings that will be swept away
heavy equiptment like bobcats, tunnel machines
disclaimer: for educational use only
this post is a work in progress, check back later for more ideas.