When there are major fluctuations in temperature, lake ice expands and contracts causing relatively loud cracking noise. The evening of January 8th, 2012 provided a virtual symphony on Taconic Lake on the Rensselaer Plateau in southeastern Grafton. Crank up the volume to hear the sound of ice expanding, cracking and "popping" in the movie clip below. The loud "clunk" you hear, about 3/4 of the way through the clip, is actually from the lake ice. For a more professionally recording of this phenomena listen to the clip Cracking Ice-Sheets Sound Like Star War Blasters.