Thats an extended move upward. It doesn't give a very good opportunity for traders to place stop orders in the market without risking losing all their gains from this pop upwards. This can lead to very sharp moves, to the downside, as traders panic and exit based on emotion. The short term traders will have placed their stops just below your support line. This is the only logical place that traders (keep in mind ALL traders are generally taught to use natural resistance points as stops...some use ma's and crap though) will have to place their stop orders.
The buy orders have been filled...and to a significant degree as depicted by this strong upmove....so what does that mean for the market.....???....LOTS and LOTS of stop orders clustered together!
Stop order filling time!