CLIMSNOW® STUDY LA ROSIERE  

The objective of the CLIMSNOW® study is to provide snowfall projections using a method developed by Météo-France (the French weather agency), INRAE (a research institute) and Dianeige (a consultancy specializing in mountain tourism development) and perfected as part of various national and European research projects.

For French ski resorts, the results presented in this report are the best available climate projections of snow cover.

Diagram above: Climate projections depend on greenhouse gas emissions scenarios.

CLIMSNOW® offers a perspective on natural and managed snow conditions (taking into account grooming and snow production) up to 2050 and also post-2050, according to the greenhouse gas emission scenarios used by the IPCC (Intergovernmental Panel on Climate Change). Among the snow-meteorological indicators that have been calculated and analyzed, the focus is on snow reliability indices, annual snow duration and snowmaking methods.

• The CLIMSNOW® methodology focuses on the study of ski areas and their ‘reliability’ in terms of snow conditions during the winter season, without prejudging changes in the availability of water resources for snow production.

• Finally, the CLIMSNOW® study only focuses on aspects linked to climate change (temperature trends, snow cover, etc.). To make informed choices about the investments and the projects selected, this information needs to be cross-referenced with other factors, particularly of an economic and environmental nature.

The models indicate that snow conditions corresponding to unfavorable seasons will increase from a frequency of around 30% in 2020 to around 50% in 2050 (groomed natural snow, scenario RCP8.5 = most unfavorable IPCC scenario, i.e. +4.5 degrees in 2100).

The 3 worst seasons out of 10 in La Rosière are seasons where we ski without difficulty for 4 months. Below are the 3 worst seasons recorded at La Rosière over the last 15 years:

**Snowfall accumulation = total snowfall between 15 December and 20 April (period during which the ski area is in operation and during which the measurements are taken).
**Average snow height = average snow height measured with a pole between 15 December and 20 April (natural, ungroomed snow).

Statistically, the fact that these 3 seasons out of 10 become the rule one season out of 2 is neither limiting nor catastrophic for skiing at La Rosière.

At an altitude of 1850 meters, the duration of snow cover is slightly less than 120 days in the RCP8.5 or RCP4.5 scenario. With the addition of artificial snow, the duration of snow cover remains well above the resort's opening period (120 days).

Diagram above: Number of days skiing will be possible in the area in question, at the altitude of the village of La Rosière (1850 m).

• Without artificial snow: 47 days of skiing compared with 82 days at present.

• With artificial snow: skiing could be possible for 4 months of the winter.

The deployment of an artificial snow network raises other issues (water resources, community acceptance, etc.), which have not yet been resolved.

Diagram above: Number of days skiing will be possible in the area in question, to the minimum altitude of La Rosière.

Cold spells will become increasingly rare in the pre-season by the middle of the century. However, CLIMSNOW® indicates that by 2050 La Rosière will have the cold snap needed to produce artificial snow (existing + planned networks).

However, the CLIMSNOW® study does not take into account the water resources.

To produce snow at La Rosière, water flows through a pipe at the La Bathie-Roselend hydroelectric plant. This pipe carries water from the Mercuel valley in Sainte Foy Tarentaise to the Roselend dam. From Roselend, the water goes to the La Bathie power station. The water collected by the ski area in this pipe reaches a first machine room (SDM1). This regulates the water supply to the Plan de l'Arc plant (SDM2).

It is here that the automated systems will distribute the pressurized water throughout the network, as well as the compressed air.

To date, La Rosière has no hill reservoir to store water.

CLIMSNOW® indicates that there is too much variability in the results for such a long period. In the modern world, ski resorts need certainty over a 30-year timescale (investment payback period).

The end of the century is too far away. On the other hand, we need to take action now (reducing greenhouse gas emissions) to avoid the worst scenarios of global warming..

Our actions, and those of the rest of humanity, have an impact on global warming in 2100. We must act now to limit the rise in temperatures by the end of the century.