Scientist inserting a snow tube
Physical Scientist Serena Matt inserting a fiberglass snow tube during the Snow Depth and Snow Water Equivalent (SWE) measurement. Sleepers River Research Watershed, Danville, Vermont.
Snow depth and water equivalent measurements have been made at Sleepers River Watershed starting in 1960. Initial snowpack measurements were made by the Agricultural Research Service joined by the National Weather service in 1966. Cold Regions Research and Engineering Laboratory started measuring the snowpack in 1979, followed by the U. S. Geological Survey from 1993 to the present. Measurements started at 2 sites, increased to 13 sites in the 1980's and currently includes 9 sites. Sites range in elevation from 200 to 670 meters and are located in a mix of fields and small openings in forests. Snow measurements were made with a 7.938 cm ID fiberglass Adirondack-type tube fitted with 40 aluminum teeth at the tip, tapered slightly inward to retain the core. The teeth make it possible to cut through ice layers and retrieve an intact core by rotating the tube. Snow depth is recorded from a rule on the outside of the tube when it reaches ground surface. The core is pulled out and weighed using a hanging spring scale fitted with a cradle to support the snow tube horizontally. Snow water equivalent (SWE) is calculated from the weight and volume of the snow in the tube. Five measurements are taken at each site, each week, nearly always between Monday and Wednesday.