We routinely keep a large stockpile of food - partly because we freeze/bottle/can/dry a lot of our own produce to last through the year, but also we generally have a good 3 months supply of all the bought-in basics - rice, pasta, flour and grain, tinned goods etc (TEA!) and bottled gas, have water filters etc. Not as a reserve against any one specific thing, but has served us well in times of sudden economic hardship/bad weather and so on.
It has occurred to me recently how vulnerable we are with regards animal feed though - we have quite a lot of chickens and some pigs, ducks etc and get through several bags of feed a week, which we buy on a weekly basis as we have no large storage capacity. If there was, for the sake of argument, major snow and we couldn't get to the ag merchants for a couple of weeks or they couldn't get supplies, we would be in trouble. I would really like to have at least two weeks animal feed in reserve but on a rented field with no outbuildings it is a problem. Not allowed shipping containers, grain bins are prohibitively expensive...