Assessment of field methods for measuring mechanical properties of snow

Abstract

Winter climates present a variety of surfaces that challenge vehicle mobility. Surfaces range from soft, virgin snow, to groomed snow and ice. This study evaluated the capabilities of various testing devices to measure the mechanical properties of winter surfaces. Concurrent satellite imagery supplemented in situ physical testing. The goals were (1) to find tests that most practically evaluate these winter surfaces for vehicle mobility and (2) to determine if imagery analysis correlates with mechanical properties, thus potentially allowing remote assessment of snow physical and mechanical characteristics.The test methods were typically useful for either virgin snow or groomed snow; no method worked well on all surfaces. Correlations between test devices were generally poor, but there were some important trends identified between (1) tests that measure the near-surface snow strength, (2) tests best suited for stronger snow, (3) the Clegg Impact Hammers and California Bearing Ratio, and (4) the optical imagery and surface drop cones. This study provides a rich dataset for assessing the current state of the art and future research needs for measurement and remote assessment of snow mechanical properties for vehicle mobility prediction.