It was interesting to see the snow cornice on the roof of the house this past weekend. When we first got there, we had about 10" of snow hanging from the roof.
Upon further inspection, you could see where it curled back towards the house, including the icicles, almost like a wave curling back on itself. It must have been a slow process where the icicles built up as the snow slowly slid down the roof.
Finally, around 1 a.m. Sunday night/Monday morning, the snow and ice made a loud rumbling and scraping sound as it broke free and created a roof avalance. I was amazed by the width of the snow field it created under the eaves. Good thing the dogs were inside when it let go.