The Snow Ripper
http://www.instructables.com/id/The-Snow-Ripper-Rip-snow-from-your-roof-in-minut/
video:
https://www.youtube.com/watch?v=zsfXoU5FoX0
Nifty device makes it easier to get snow off of your roof.
Silverbear Snow Scoop
https://www.youtube.com/watch?v=ffyPN2-EDg4
That is a good way to get killed. Notice he has the ladder set up where it will tip sideways and fall over when a bigger chunk hits it.
I agree that trying to get some off the roof is a good idea but ladders are funny if you don’t understand them well.
I have seen guys try to pull a little section and a warm roof allows the whole roof load to slide a once — baaammm.
Here’s something like the Snow Ripper but bit better especially since you don’t need a ladder to get the snow off the roof.
https://www.youtube.com/watch?v=JwnhZNYSbwk