Keep this in mind

You should use a roof rake to clear at least a few feet from the edge (eaves) of the roof to prevent ice dams.When the ice builds up high enough, the water from the snow melting can't run off the roof, allowing it to find a way under your shingles. The pitch(slope)of your roof is also a factor if you have a steep pitched roof you have less to worry about. The weight of the snow is distributed more to the outside walls if the pitch is steep, and more onto the rafters if the pitch is low.The snow MUST be removed if the forecast calls for rain.The snow will act like sponge holding the water and adding an incredible amount of weight.