Answers

Dear John

We've encountered lots of ice damming in the the Chicago area.   I agree with you, don't go on the roof now, it's too dangerous.  Attic/roof ventilation and insulation are key factors in the creation of ice dams.  If you're experiencing active leaking into your home now I'd consider using a snow rake w extension pole( while standing on the ground) to pull the snow off the leaking ice dam area.   This might slow down the leaking by exposing the snow/ice melt area and decreasign the amount of snow melt contributing to the ice build up.   

When spring comes, and it will!  Consider installing a quality gutter/downspout snow/ice melt system in the problem areas.  We've used the engineered systems made by WarmlyYour's http://www.warmlyyours.com/en-US/snow-melting/roof-deicing to solve ice dam problems for many of our clients.  See the attached photo of a client's home in Wilmette, Illinois 60091 with a snow melt system actively working.

Once again- stay off the roof ! 

Best wishes

David Roberts 

Roberts Construction Group