Does a steeper skew presage a crash?

The S&P skew has steepened significantly of late. Does that mean anything, other than more buyers of downside options? In particular is there any evidence that a steeper smile is associated with large moves down? In the other direction it works - if there is a big fall then vols rise and the skew steepens. But I know of no studies that suggest skew steepening is a useful predictor of falls. It would be interesting to know though... after all, we are close to the anniversary. Certainly it seems likely that with all the press coverage, the big 2 0 is spooking investors. But of course that doesn't mean we won't have a crash.