Ice Dams on My Roof - Help!!

[Snowtractor]

Manual Labour is in town and I hear you're going to use him :-)
2 pound hammer and like appilcation of force will shatter the ice while still cold. If you wait too long and it warms the ice will Toughen become pliable near 0 degrees and above. You should be able to do it all from a ladder , it is eaves anyway, just ensure the ladder sticks at least 4 feet above the eave edge.
Also you can remove all the snow as in Alex's excellent suggestion and get a snow rake to do it from ground level from CANUCK WHEEL.
Hot water on cold roof...hmmm rapid expansion cracking delamination of roofing material and possible plywood underneath...I don't suggest it, but take pics if you do :-).
Lastly if you go up the tie a rope over the roof to a NON MOVING article haevy enough to support you. Keep the freeplay short to reduce shock loads and taunt nearer the eave edge.
Just a note I have to clean ice off my roof where the kitchen fan and bathroom fan exit under 2 feet of snow twice a winter. In 10 years there has been no damage to my roof , but no shovelling sideways or up...PERIOD ! only down and bang with a blunt object, middle managers make good bangers or back side of axes or 2 pound sledges.
Sean