VALIDATION STUDY OF AVATECH'S RAPID SNOW PENETROMETER, SP1

We validate early prototypes of SP1, a light-weight rapid-push snow penetrometer devel- oped and produced by MIT-based start-up AvaTech. The device records snowpack hardness profiles and other information as an integral part of a snowpack observation system. Using SnowMicroPen (SMP) profiles, manual profiles and other observations, we evaluated the depth and force readings of SP1 profiles. We collected comparison data at sites in three mountain ranges in Idaho and from an ice cap in northern Greenland. Pits contained a broad range of hardness (including new snow and numerous crusts) and moisture content (dry, moist, saturated, and mixed conditions). Initial comparisons indicate that SP1 profiles recorded stratigraphic features also observed in SMP profiles and manual profiles. Force values appear to be consistent between profiles at a given field site. Truncation of near-surface measurements was fairly common, and errors in absolute and relative depths existed in some profiles and not in others. Possible contributing factors may include 1) the ranging unit's accuracy when starting a test (~1.5 m above snow surface), 2) solar transmission through the upper snowpack delaying surface identification, 3) the ranging unit's sampling rate may have been too slow for tests with high push rate variability caused by hard layers, and 4) the post-processing depth algorithm. Improved depth measure- ments will allow for its application in slab thickness estimates and possibly weak layer identification. The SP1 has the potential to become an accurate and efficient tool for snow professionals.