Design and performance of the NVE snow scales

Abstract

Continuous information on snow water equivalent (SWE) is of great importance in the natural hazard assessment (i.e. snow melt floods), in power production planning, water supply forecasting and more. In 2009 NVE designed and developed a new electronic snow sensor: The M2525. The main goal was to develop a sensor that was better than a snow pillow with respect to measurement errors as well as being more robust and less prone to defects. This study investigates the performance of the M2525 and the two smaller snow scales, the M604 and M910, at six study sites from 2009 to 2023. The performance of the scales is validated against manual snow surveys. I addition we have used exploratory analysis of the time series with the purpose to detect and discover typical patterns of measurement error.The largest snow scale, the M2525, seems to overestimate SWE by a ratio of +0,14 compared to manual surveys. However, M2525 does not seem to have trouble with pressure relief of the same magnitude as a snow pillow. Data analysis from the smallest scales showed both over- and underestimation, as well as small signs of measurement errors indicating that further observations and analyses are required.