The price just reflects how much people want in and out.
It seems like many people expect the dollar to collapse, so many people want in. When all of those people have exchanged their dollars for bitcoins, who is going to exchange them next? If no more people are in line, the value will drop back to where it was at the beginning of the year.
The beauty of a fiat currency is that you can maintain its value simply by adjusting supply. Is there any sign that there is an over-supply of dollar which would justify leaving the dollar until it is crashed?