0. No requirements/ minimal requirements
Easy rides on comfortable, not so deep powder snow, with gentle run outs and without any steep slopes, no narrow sections and few to none trees and obstacles on the way down. On the way up there are gentle slopes, all no steeper than 30-35 degrees.
Rides on deep powder snow, or wet spring snow sometimes with thin crust. There are occasional 35 degrees inclines, with some steep sections with well spaced obstacles and enough space to maneuver on the way down. On the way up there are gentle, not too narrow slopes.
Tracks with different conditions, including powder snow, as well as crusts and hard packed snow. Multiple sections with inclines of 35 degrees, and narrow sections in dense forests on the way down, but still with clear, fluid lines to follow. On the way up, there are multiple steep sections of 35+ degrees, some narrow and may require crampons and/or other special equipment.
Rides with a wide range of track conditions, varying from powder to hard packed and wind-blown snow and ice. Multiple sections with inclines of around 35 degrees, narrow couloirs and ridges, dense forests and other obstacles on the way down. On the way up the slopes are quite steep, with some sections over 40 degrees. The use of crampons and special equipment is almost certain.
Multiple varying conditions across the route with large segments of very hard icy snow. Very steep slopes of 55+ degrees, narrow sections, requiring a high level of control on the way down. On the way up inclines are as steep as the snow can hold. Using ski-alpinism techniques is required, including belay.