Periodic Reporting for period 2 - PROSNOW (Provision of a prediction system allowing for management and optimization of snow in Alpine ski resorts) Période du rapport: 2019-03-01 au 2020-08-31 Résumé du contexte et des objectifs généraux du projet Ski tourism is deeply rooted within the economies, culture and livelihoods of European countries, within and outside mountainous areas. Climate change impacts and risks are increasingly recognised as a major threat to ski tourism. Indeed, ski tourism relies on snow on ski slopes as its main resource. The natural snow cover is highly variable from year to year and is undergoing a substantial decline, especially at low elevation, due to rising temperature. In order to reduce the impact of the variability and reduction of the natural snow cover, and secure its operating conditions, the ski tourism industry has massively developed technical snowmaking, a.k.a. artificial snow. Artificial snow is usually produced early during the winter season, in order to provide a base layer required to fully exploit early natural snowfall and ensure, as often as possible, satisfying snow conditions for the critical season start, especially the Christmas holiday period, and then secure the rest of the winter season. Snowmaking bears a significant cost among ski resorts operating cost, hence optimising its use has a direct economic benefit (Figure 1). Furthermore, its operations use environmental resources such as water and energy. This impacts the local landscape, ecosystems and water cycle, and contributes to the broader environmental footprint of human activities at all spatial scales. Ski tourism therefore faces climate-related challenges at various interconnected time scales: how to efficiently adapt to ongoing climate change, now and in the future, using effective methods to cope with variable and declining snow cover, without committing to detrimental effects to the local and global environment in the long term ? Several studies have documented the long term impacts and risks of various climate change scenarios on snow reliability in ski resorts in various mountain areas (IPCC, 2019). Complementary to long term climate change impact studies, the development of early warning systems is recognised to enhance the adaptation capacity of socio-economic sectors (IPCC, 2019). In this context, the initial motivation of the PROSNOW project was to contribute to developing early-warning systems to better cope with the impact of the variability of meteorological and snow conditions on ski resorts operating conditions and better adapt to increasingly challenging conditions in the future. One key requirement for early-warning systems is the provision of impact-based forecasts, at relevant time scales, designed to adapt operations, in real time, to expected upcoming conditions, in order to reduce their potential negative impacts or benefit from upcoming opportunities. Travail effectué depuis le début du projet jusqu’à la fin de la période considérée dans le rapport et principaux résultats atteints jusqu’à présent The PROSNOW project brought together 13 academic and industrial partners operating in the field of the mountain snow cover in more or less direct relationship with ski tourism. Numerical snow cover models simulate the evolution of the snow cover, based on the time evolution of meteorological conditions (temperature, precipitation, wind speed, incoming radiation, etc.). PROSNOW has enabled further development of such models to account for grooming and snowmaking in a physically sound and operationally meaningful manner. Such models need to be fed by meteorological information, and the PROSNOW project has consolidated methods for feeding such snow cover models using not only past observations but also forecasts across weather (days to weeks) to seasonal (weeks to months) time scales. Because of the various sources of uncertainty involved, so-called 'ensemble forecasting' was implemented, which provides a range of meteorological scenarios at various lead times, based on the output of numerical weather models, based on which probability ranges for the upcoming conditions can be inferred. The PROSNOW system (see Figure 2) combines an ensemble of meteorological and seasonal forecasts with an ensemble of model configurations, enabling to quantify the impact of various snow management tactics, and therefore provide objective information to guide decision making in real time (see Figure 3). Based on a detailed representation of the geographical organisation of the ski resort, the system makes it possible to identify the subsectors of the ski resorts with most challenging snow conditions and provide a forecast of water consumption for snowmaking associated with each option (Figure 3). In situ measurements of snow depth (using sensors embarked on grooming machines) or snow production can be used, in the PROSNOW system, to adjust the simulations and enhance the realism of the results. Functional choices relevant to the development of the main configurations handled by the system and the design of the user-facing tool were developed thanks to a co-design approach involving pilot ski resorts. These specifications were confirmed by a wider-ranging survey across ski resorts in the European Alps. Progrès au-delà de l’état des connaissances et impact potentiel prévu (y compris l’impact socio-économique et les conséquences sociétales plus larges du projet jusqu’à présent) The PROSNOW project delivered its expected results, i.e. a fully operational modelling and data visualisation system tailored to the needs of ski resorts managers. It has developed a dedicated advanced programming interface (API) for exchanging snow-related information between ski industry service providers and stakeholders, thereby enabling an acceleration of data sharing in this sector. All software dedicated to operating the PROSNOW data server and user-facing tool has been deposited on a code repository, with access restricted to project partners until August 2023, after which the software will be openly available. This will enable additional stakeholders in this field to benefit from PROSNOW results, without endangering the commercial exploitation of the service by the organisations which have invested time and energy in its development. PROSNOW has also delivered improvements of existing open-source software elements, with immediate benefits to their community of users (e.g. snow cover models, or tools for the post-processing of seasonal forecasts). Scientific results from the PROSNOW project have been published in open access journals.During winter 2019–2020 (the last winter of the project), pilot ski resorts were able to test in real time the user-facing tool from PROSNOW and assess its added value for their daily operations. Based on their feedback, and a complementary analysis, potential water savings, which would arise from better optimisation of the use of this resource, amount between10 to 40 per cent of the total annual water consumption within a given ski resort, corresponding to hundreds to millions of euros per year, depending on the size of the ski resorts. Such figures and generally positive feedback from the pilot ski resorts and industry experts exposed to the PROSNOW user-facing tool (online showcase available here: https://prosnow.org/get-to-know-prosnow/) confirm the relevance of the initial vision of an early-warning system fostering the adaptation potential of ski resorts (Figure 4). Work is in order to bring this service to the market. This is currently taking place in the form of various exploitation entities, consisting of one or several partners of the PROSNOW project, pooling resources and ambition in order to commercialise the PROSNOW service in various markets. For example, one exploitation entity targets the French Alps and Pyrenees market (including Andorra and Spain), while other exploitation entities target the Northern Italy and Swiss markets, and Austria. PROSNOW service supply chain. Ski resorts operating costs (left) and unpacking of snow management cost elements (right). Snapshots of the PROSNOW user-facing tool. Feedback from pilot ski resorts after one winter of testing of the PROSNOW service.
