As I write this the S&P 500 is down nearly 3% in what is the worst day for US equities since 2011. However, it is worth noting the S&P 500 is now testing an important area of support/resistance dating back to the end of last year:

Click to enlarge

SPX_Daily_10.15.2014

While there is panic in the air and anything could happen, it will be interesting to see if the selling abates here. Should the S&P knife right through 1800 it will be a strong indication that this isn't going to be your garden variety market correction.