The report explores the eects of track preparation in alpine and cross country skiing areas. The rapidly evolving state of the art and the high customer demand are pushing the ski resorts to dedicate an increasing part of their budget to the production and grooming of piste snow. However, the precise processes that snow undergoes during and after preparation are still poorly understood and often insuciently monitored. In the rst part of the report, the precision of two handheld prototypes was tested: a density sensor and a specic surface area sensor. Those tests were performed to assess their reliability in a piste environment. Secondly, results from eld work campaigns on the Lenzerheide ski resort and the Davos cross country tracks are presented. This section aims to determine the importance of the meteorological and snowpack conditions in the evolution of the ski track. In the last chapter, the report tests the one dimensional snow cover model SNOWPACK in a groomed snow environment. Finally, the results from the previous sections are used to improve the snow preparation module recently implemented into SNOWPACK. The study found that the handheld density sensor consistently underestimated the density of the snowpack by 20%, which required to apply a correction to the eld data. The high uncertainty showed by the specic surface area sensor on old technical snow made it not reliable for the purpose of this project. The results from the eld work campaigns found that the dierence between the preparation on an alpine ski piste and on a cross country track is minor. The cloud cover has been observed to have a strong in uence on the temperature gradient in the snowpack, which can have an in uence on other parameters such as hardening. The investigation made on new snow showed that a slope needed four to ve days of grooming to reach its nal state. Finally, the SNOWPACK model appeared to be accurately simulating the temperature gradient in the piste, and the grooming module showed signi- cant improvements thanks to the better implementation of snow parameters. This study provides important information about the monitoring and modelling of a groomed track. Therefore, it will help practitioners and researchers to better understand the processes that aect the snowpack after the preparation.