Blade Hardness Gauge: Snow Hardness Measuring and Analysis Techniques

Abstract. The blade hardness gauge (BHG) is a promising technology for avalanche forecasters, technicians, and researchers. Designed and produced by Fraser Instruments Ltd., the BHG resembles and is based on the thin-blade tool introduced by Borstad and McClung in 2011. The BHG was designed to quantitatively measure snow hardness without the known biases of the hand hardness test. Research was carried out in the Canadian mountains of British Columbia and Alberta during the 2020–21 and 2021–22 winter seasons to test the reliability and integrity of the BHG. Side by side snow hardness profile comparison amongst avalanche practitioners shows that the BHG is more consistent for measuring snow hardness than the hand hardness test. A blade hardness to hand hardness comparative scale was developed to utilize the BHG as a teaching tool for the hand hardness test. This paper proposes refinements to standard data collection methods and techniques including the insertion rate and orientation of the thin-blade into the snowpack. These recommendations aim to increase consistency amongst users and highlight applications for avalanche practitioners to use in the field.