Kind of a vague question pard.
Is there an ice dam on the north side? If so, there is a serious insulation/ventilation problem.
If it's merely a pile of snow, use an aluminum scoop (grain) shovel. Be careful of the shingles and gutters (gutters should be cleaned or removed by now). Make sure there is no expensive shrubbery below.
Heat wraps are no match for mother nature.
A healthy layer of snow on top of a well built roof is only added insulation.

EDIT: For crying out loud, never use salt on anything except sidewalks.