The market continually changes between periods in which the prices stays placidly within trading ranges and, if it moves, moves smoothly and continuously, and periods in which it moves violently, retracing large movements within days and making huge movements within weeks. There is a loose correlation between higher volume and higher volatility. Right now, volume is moderately low. Volatility has been high since the major rallies in May, with record weekly price movements. The exception is late August and all September, in which a stable trading range was created.
Prices still have some room to move down.
There should be a some weak support around 200, and stabler support in the low 190s. It hasn't dipped below that in a while, but if it's able to it should punch through the support at 180 and keep dropping until it hits the heavy support in the upper 150s like it did in July. The three peaks it's made in the 220s, each successively higher, should be considered strong resistance. One good short-term strategy might be to short futures with a tight stop and an objective in the low 190s. Over the long-term, volatility may increase again.