SGR SNOW HISTORY 1980-2012 This movie shows the snowfall year-by-year, since the winter of 1980-81. Each year's data are displayed for about 1 second. The heavy black line is the average since 1982. The peak snow depth occurs about April 10, on average. The snowiest winter was 1983-84. Snow data are from the Snotel Summit Ranch recording station on Rock Creek. At this station, snow is weighed on a 'snow pillow' and data are converted to Snow Water Equivalents (SWE) - equivalent inches of water.