Cold air crosses warm water, picks up heat and moisture from below, becomes unstable, and dumps everything downwind. That is the entire machine.
Three numbers run it: the delta-T between the water and 850mb (13C is the usual threshold), the fetch along the lake axis, and the inversion height that caps how tall the band can grow.
Wind direction decides who gets buried. A ten-degree shift moves a band twenty miles, which is the difference between three feet and three flakes.
Single bands are the extreme ones. Multiple bands spread the snow around and are far less dramatic, which is why the single-band setups are the ones I lose sleep over.