Ski domains ranked by how much of their piste sits above a snow line you choose, to find places that are both big and likely to have snow early and late in the season.
How it's measured
Every downhill piste is mapped as a line with an altitude at each point. We split each line into short segments, measure each one's horizontal length, and add it to the 100 m altitude band at its midpoint. A domain's total is the sum of its bands, and "above the snow line" is the sum of the bands above it.
Only operating downhill pistes count. Ski routes, freeride and backcountry runs are left out, and so are pistes mapped as areas rather than lines, because they have no length to measure. Grades follow the European colours: OpenSkiMap's novice is green, easy blue, intermediate red, and advanced or expert black.
Why sizes differ from resort brochures
Figures here are usually lower than a resort's published piste km, sometimes by a lot. Resorts measure in different ways: some count ski routes and itineraries, the length along the slope rather than on the map, wide pistes as several runs, or the whole of a lift pass that covers unlinked valleys. Our figure is the horizontal length of the pistes mapped in OpenStreetMap, measured the same way everywhere, so it is best used to compare domains with each other. Where a domain looks too small, its pistes may simply not all be mapped yet.
Linked domains
Domains come from OpenSkiMap, which groups resorts into linked areas such as Les Trois Vallées. With "Linked domains" on, resorts inside a bigger domain are counted as part of it, and lift-pass networks of unlinked valleys, such as Dolomiti Superski, are hidden. A few linked domains aren't grouped in the data yet, so their resorts appear separately.
The snow line
The snow line is a single altitude. It doesn't account for which way slopes face, latitude, glaciers or snowmaking, so treat it as a guide to altitude rather than a snow forecast.
Fixing or adding data
All pistes and lifts come from OpenStreetMap, via OpenSkiMap. If a piste is missing, misnamed or has the wrong grade, you can fix it in OpenStreetMap: the piste mapping guide explains how pistes and lifts are tagged, and OpenSkiMap explains how its ski areas are built and how to report problems. Changes reach OpenSkiMap within about a day, and this site picks them up at its weekly rebuild.
Data and credits
Piste, lift and ski area data © OpenSkiMap and OpenStreetMap contributors, available under the Open Database Licence (ODbL). Map tiles from OpenFreeMap and OpenMapTiles; terrain from AWS Terrain Tiles.