Ski Trails Designation System
Ski trails are categorised by difficulty and the system is obligatory across Europe. Trail markers consist of a rectangular yellow plate with a coloured stripe running from left to right, the stripes either green, blue, red or black (a four-level system). Green trails are easy; blue trails are more difficult; red are the most difficult, black are extremely difficult. Additional signs, similar to those used on roads, warn skiers of curves, narrowings, junctions and other potentially dangerous places.