Yep, I'm all too familiar w/ice damming (MI resident here) and this is not ice damming. Notice the absence of any snow or ice on the surrounding roof structure and/or the remaining circumference of the pipe. Also, this is at the peak of the roof not over the soffit areas.
My attic is blow pink fiberglass and I hate that stuff w/a passion. By the time I get out of the attic, I'll be wearing it. However, if this can't be tackled from the outside, I'll have no choice.