As exciting as today's action was, it was not a follow-through day because today's volume was lower than Friday's volume. The Nasdaq 100 was the weakest of the large cap indexes which is not a good sign either. For the SP500 1100 to 1104 should prove to be strong resistance going forward.
The chart above of the IWM shows that it has merely retraced back to its broken channel line. While the 200dema offered recent support (green arrows), notice how the median line proved to be significant resistance (red arrows) during the first leg of the rally. Now that the lower channel line is broken, it should also prove to be significant resistance.
From the bullish perspective, there should be some additional upside after today's advance. The higher wave B goes, the more the downside in wave C will be mitigated once it gets underway.