In this photo taken by Jim Bromley you see a large amount of snow sliding off of a metal roof. In some ways, the snow on the roof is acting like a glacier where slippage is facilitated by water at its freezing/melting point creating a nice lubricated surface between the snow on top and the metal roof beneath. As you can see in this photo, a lot of stress is being put on the rain gutters and the plants beneath are about to be pummelled by some heavy snow falling on them. Snow Guards can help to prevent this snow slippage and catch the snow and ice before it hits the ground.
Posted by Roof Things on 1/21/2011 to Sliding Snow