It's good to see that you're interested in knowing 'the facts' before you start doing any work to fix the problem.
The good news is that the WEB is full of information on this subject. Since there are a plethora of reasons for ice damming, it's best to search the WEB for discussions on the topic. Here are a couple of ideas.
Select your favorite WEB search engine (or ask a friend who knows how to use one if you are not familiar with them). I use Alta Vista mostly to do my searches. From there, I enter in +"ice damming" & +prevent ,EXACTLY, and press the Search button. This will generate a list of WEB sites that discuss ice damming and ways to prevent it. Give this one a shot. One particular WEB page that I liked on the subject of ice damming is, Ice Damming. You can 'walk' through the 4 pages on the subject.
You might seem over-whelmed but if you are, again, I suggest you find a friend and buy them a few beers (to drink later on, of course) in exchange for showing you how to do WEB searches for info. It's a great thing to know.
Best to ya, and if you find a minute, let me (us) know how you made out in your searches.