Spatially distributed snow depth and snow duration data were collected over two to four snow seasons during water years 2011-2014 in experimental forest plots within the Cedar River Municipal Watershed, 50 km east of Seattle, Washington, USA. These 40 m × 40 m forest plots, situated on the western slope of the Cascade Range, include un-thinned second-growth coniferous forest as control treatments, variable density thinned forests, forest gaps in which a 20 m diameter (approximately equivalent to one tree height) gap was cut in the middle of each plot, and old growth forest. Together, this publicly available dataset includes snow depth observations from manual snow courses, distributed snow duration observations from ground temperature [...]