The Swiss Alpine Club has the following ratings for ski tours (in German here):
- L (easy/ “leicht”): Slopes less than 30°
- WS (moderate / “wenig schwierig”): Slopes sometimes > 30°, some zig-zagging needed
- ZS: (advanced / “ziemlich schwierig”): Slopes somestimes over 35°, sometimes narrow/steep terrain
- S: (difficult / “schwierig”): some slopes > 40°, exposed parts with cliffs, only recommended for experienced skiers/moutaineers, slides/falls can lead to deadly injuries
- There for further grades such as SS, AS and EX (“extrem”).
Routes WS and higher can be dangerous in avalanche conditions 2 (“moderate”) or higher. L routes are usually safe except in high avalanche danger (when usually ski tourers stay at home anyway).
Depending on the author of the regional SAC ski touring guides the ratings can wary considerably, i.e. ratings in Central Switzerland are usally higher than in Grison.