First, copper is also basically crashing, just as oil has been, to little fanfare. The first chart, below, of the daily timeframe for the cooper ETN indicates as much. Although "Dr. Copper" has not been a good market tell since about 2010, the violence of the selling is something worth noting, and another reason to not get too complacent regarding the resilience of the equity markets.
In addition, Russia, seen on the country ETF daily chart, second below, is dripping down towards another breakdown in what looks to be a morphing bear flag. The only suspicious part for bears if the lack of acceleration lower in the selling. So let's see if that comes into play soon.