An automated quality control procedure for the water equivalent of snow on the ground measurement

Snow water equivalent (SWE) has been measured daily by the United States National Weather Service since 1952 whenever show depth is 5 cm or greater. These data are used to develop design snow loads for buildings, for hydrological forecasting, and as an indicator of climate change, but have not been subjected to quality control. The quality control procedure developed here for the northeastern United States checks daily SWE measurements for common digitizing errors, values beyond reasonable limits, and consistency with daily precipitation and melt. Potential effects of drifting and the intrinsic micro-scale variability of SWE are also considered. A daily SWE measurement is declared suspicious if a sufficient discrepancy is found between the measurement and the expected SWE. Data flagged as errors are checked manually.