a rational panic

As I've been saying for the last five years or so, buy real assets and get rid of your paper savings. This terrific analysis on seekingalpha.com goes into the structural issues in some detail. Key issue:
...If users of a currency find that it loses value such that savings and wages are perceptibly eroded before they can be utilized at fair value, the rational course of action is to shed the currency as quickly as possible.

This sparks a competition to shed currency in favor of real goods and, once the process begins, the rational course of action is to participate in the proverbial rush to the exits. Interestingly, a panic is not required to explain this phenomenon.