NASA has a very good video on tailplane icing. I did my undergraduate research project on the subject (tailplane icing) and learned a great deal from NASA. Im not attributing the blame to this accident on tail ice and subsequent stall, it is however a viable theory. I think all aviators and non-flyers alike, will find the video informative and educational on the basics of aerodynamics and the affects of ice accretion (especially on the tail). Fly safe.
Tailplane Icing