Geo-informatics data acquisition instrument for assessment of avalanche risk and trafficability: STMET

Abstract. Off-road soil conditions and snowpack strata data are traditionally acquired with cone penetrometers and ramsonde rods to assess trafficability and snow stability. The Snow and Terrain Mobility Evaluation Tool (STMET) has been designed and developed as a multi-utility instrument for snow and soil to acquire geo-informatics data. Load cell, moisture sensor, temperature sensor and data transmission modules in small form factors are embedded in the rod-like instrument for easy movement and for finding penetration resistance, moisture and temperature profiles of the snowpack and soil. One of the cone angles (30, 45 and 60°) of the cone assembly is auto-detected by the data acquisition system for ease of set-up and data storage depending on geophysical conditions. Laser-based ranging sensors continuously monitor cone penetration depth. The profiles of snow strength, moisture and temperature are displayed on the detachable display in graphical form, which helps to find the weak layer responsible for avalanche occurrences. The positions of the experimental site and the terrain slope are obtained with the Global Navigation Satellite System (GNSS) and Inertial Measurement Unit (IMU) built into the system. The transmission module of the system transmits the data and an alert signal to a distance in case of emergency. The catchment area of an avalanche site is measured using an algorithm based on the data obtained with a distance-measuring sensor and roll–pitch–yaw data of the IMU. The enhanced capability of the instrument for trafficability assessment is feasible by comparing the Soil Cone Index (CI) and Vehicle Cone Index (VCI). The decision support system (DSS) has been implemented as a tool for soil, snow stratigraphy, avalanche and victim detection to ease the decision-making process for assessing trafficability and avalanche risk. This paper highlights the concept and features of the Snow and Terrain Mobility Evaluation Tool (STMET), which is capable of acquiring geo-informatics data for scientific applications in challenging terrains.