I'd note that completely inelastic supply almost never occurs, even in a disaster. For example, if prices for water are high, it raises the likelihood that some

I'd note that completely inelastic supply almost never occurs, even in a disaster. For example, if prices for water are high, it raises the likelihood that some entrepreneur will fill up a truck with water bottles and drive into a disaster zone to sell them. Or that a shopkeeper will stay open past his normal hours, or not set aside a bunch of water bottles for himself. And of course there are dynamic effects of anti-gouging laws, too. Even if supply were unchangeable during a disaster, the knowledge that prices will--or will not--be allowed to rise when a disaster occurs change how shopkeepers will prepare when a storm is approaching.