This was really sad. I heard a little bit of the voice recorder. The situation went from moderately bad to mayday to catastrophy in less than 60 seconds.

Here's my understanding of what they believe happened: They appear to have flown directly into a thunderstorm which caused ice to build up very rapidly. That ice buildup caused a loss of control which caused the plane to bank hard to one side, most likely stall, then spiral straight down.

The sheer terror everyone must have felt in their final moments is what haunts me.