SGR SNOW HISTORY 1982-2004 This movie shows the snowfall year-by-year, since 1982. 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. 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.