The heat from the sun is causing partial thaw then it refreezes because the heat doesn't last long enough. As long as the water isn't making it into the house don't worry about it. That's what that rubber membrane 6 ft up is to prevent leakage.

Yea,..don`t worry til your gutter and fascia are on the ground !!

I had a terrible time with ice dams this past winter, but I found this video on ice dam prevention and I'm going to try some of the tips next year; hopefully that will help.