That's a great article.
I've never witnessed an avalanche, but in September of 1999 a group of us actually heard the most recent slide on Mount Colden. Hurricane Floyd was to blame after having saturated the ground within the past week. We were backpacking in the area, bagging some peaks, and had made camp that night about a mile from the shelters at Marcy Dam to avoid the crowds. We heard a strange rumbling, and one of the guys swears he felt it. At the time, we all wondered if that had been a landslide, but dismissed it for lack of knowing. We figured there had to be some other logical explanation (wind, imagination, thunder, earthquake?) The next morning, as we reached Marcy Dam, a helicopter was hovering near the freshly scarred mountain. A ranger gave us the scoop and pointed out the massive slide. It was amazing.