the snow will insulate the ice and generally slow the ice making down or in some cases stop making ice if the temps are borderline of the freezing point,also sometimes the snow will cause a layer of slush under the snow making it sloppy,this tends to happen with a wet heavy snow as over time the moisture will settle out of the snow(water runs downhill) and turn to slush the wetter the snow the more slush,dry snow on the other hand tends to blow off of the ice and build up towards shore larger lakes see this mostly,I remember trudging through 3 feet of snow on the shore of lake aerial and the farther from shore we got the less snow there was,if we get a wet heavy snow its not going to help with making ice on the lakes lets hope for the best
