It is easy for an economist to think that letting price allocate the resource is always the best way, but the owners of the stores often had other concerns. For example, a hardware store that has a regular clientele may fear that raising price may alienate regular customers and cause more harm for his business in the long run. A large hardware chain may want to use first-come-first-serve since the extra money from raising price may not outweigh lost goodwill, both in the stricken area and elsewhere. One of the advantages of markets and private enterprise is that multiple solutions to a problem that can coexist. One solution, not even price, is always the best solution for all.
That said, I am puzzled by the emotion that "price gouging" can raise. One response of people to the possible damage Rita may do to oil refineries is to race to gas stations to fill up their vehicles before prices go up. This seems as selfish and egoistic an act as the gas station owner who raises price anticipating a shortage. Yet, the latter behavior is condemned and the former receives no comment.