Ice dams are much less likely to form if the gutter system is free of debris.
Rather than rewrite what has already been written so nicely, check out the article on This Old House. To sum it up ice dams form from melting snow on the roof which may melt at a warmer section of the roof and as it meets the edges re-freezes. Icicles may look beautiful, but the ice building up beyond them on the roof line can lead to big trouble.
If your icicles are minor in size, your ice dam is probably on the smaller side as well. Consequently, the possible damage would most likely be only to the gutters being pushed away from the home- a minor gutter repair that can be tackled in the Spring. However, it's really a big guessing game until someone gets up there to see how massive the ice dam is.
The major trouble is when the ice dam pushes up roof shingle and causes water seepage into the home. Newer homes are being built with ice/snow shields, a rubber sheet, that should protect from this problem. However, if you have an older home that doesn't have it, your ice dam is several feet up the roof, or if the builder skimped on the standard 32" height; you will want to get that ice dam broken up.
We have been getting several calls for ice dam removal this week. Homeowners that are not equipped with a ladder to reach the issue are seeking the help of a professional. When researching the issue, I found that there are companies with trucks equipped with a heated water supply. Where are they? Well not in our area. My method is simple- I am climbing the ladder with one gallon of hot tap water at a time. Piece by piece, I break up the ice dam until the gutter is cleared and water flows down the spout. If you call us up, please be prepared to refill our supply of hot water to complete the job.
