Anticipating future snowfall in ski resorts to guide development choices

La station de ski de Megève en hiver © Nicole Sardat / Irstea
La station de ski de Megève en hiver © Nicole Sardat / Irstea

Will there be snow this ski season? This is a recurring and important question for snow resorts that need an organized response to the effects of climate change. In Grenoble, scientists from Irstea and the French Center for Studies of Snow and Weather have designed a unique long-term projection tool for resort snowfall, taking into account snow management practices. The Isère department decided to make use of this tool as part of an overall study on snowfall and development choices for its skiable areas.

Faced with later and more uncertain snowfall, winter sport resorts (particularly those in mid-mountain areas) need to adjust their operating models. Although managers have learned to accommodate natural variability in snow cover (packing the snow to stabilize it, producing artificial snow), the drop in snowfall predicted by climate projections will weaken the economic model of these regions. Currently, two action strategies are being considered: increasing the reliability of snow cover and diversifying tourist services. As a pioneer in diversification, the new Auvergne-Rhône-Alpes region recently implemented a Snow Plan to support the development of production infrastructure for artificial snow: snow cannons and a snow creation network. In accordance with the regional plan, the Isère departmental council has decided to base its subsidy decisions for equipment projects on a diagnostic process defined by scientific knowledge and tools, developed by Irstea and the French Center for Studies of Snow and Weather (CEN) 1.

A snowfall modeling tool that can be applied to large areas

The diagnosis is based on the unique Crosscut tool. By combining a spatial model of all the ski resorts in France (work carried out by Irstea using the BD Stations database 2) with a model of the snowpack using meteorological data collected between 1958 and 2014 for all mountain ranges (SAFRAN-Crocus model developed by CEN), the tool can be used to assess snow cover for skiable areas, taking into account their geographical and topographical characteristics (mountain range, altitude, slope, orientation). The tool offers two other essential features:

The aim? To estimate the level of snowfall for ski runs (packed, with or without artificial snow) across a given skiable area for each season to 2100!

Snowfall simulation for the Arcalis resort (Andorra)
Snowfall simulation for the Arcalis resort (Andorra) with natural, packed, snow (in the center) and the production of artificial snow (on the right): number of days with enough snow to open the resort.

Key data for resort development in Isère

Applying this model chain to the 23 resorts in Isère and analyzing the data obtained helped scientists reveal several types of results. Firstly, the project resulted in the creation of a summary document for each resort, containing historical data and snowfall maps (from 1958) as well as future maps to 2050 and proposals for various scenarios to expand the runs equipped with snow cannons.

Additionally, snowfall projections were used to evaluate the impact of creating artificial snow on water resources. "Across the 23 resorts, we showed that up to 2050, an increase in areas equipped with snow cannons will have the most impact on the amount of snow being created and therefore the amount of water required. However, after 2050, climate change will become the defining factor in increasing snow creation if the number of snow cannons remains unchanged. This shows the cumulative effect of water resource pressures that need to be taken into account for future developments. Elsewhere, based on an overview of development projects currently planned by the 23 resorts, we found that overall water consumption would increase 2.5 to 3 times between 2001 and 2025," specifies Hugues François, engineer at Irstea's Mountain Ecosystems and Society Laboratory.

All this information, especially the summary documents produced for local authorities, combined with studies carried out by other project partners on the impact of an increase in snow production on water resources and financial investment, should now help decision-makers choose which development projects they consider suitable to support development in their region.

For more information

Partners of the research agreement: Irstea, Snow Research Center (MétéoFrance-CNRS, UMR CNRM), NaturaScop, KPMG.

2- Developed by Irstea, the BD Stations database brings together data on the equipment, organization and management of French ski resorts. It's available through the online interface: Stationoscope.

3- Intergovernmental panel on climate change.