Since I first started tracking BTC using various TA methodologies, one thing that I've noted time and time again is that BTC seems to very often settle into distinct channels that it trades in for extended periods of time.
Over the last four months, those channels gradually got steeper and steeper without there ever being a significant retracement. This meant that when the retracement came (and it always will), that there was a whole lot of unaddressed area in the chart that needed filled in (i.e. a significant price drop in a rapid period of time).
Following the recent significant retracement BTC appears to be trading again in a much more moderate channel. Here's hoping that it stays this way for a while!