Rock scrambling or easy snow slopes; some glacier travel; often climbed ropeless except on
PD: Peu Difficile/a little difficult.
Some technical climbing and complicated glaciers.
AD: Assez Difficile/fairly hard.
Steep climbing or long snow/ice slopes above 50 degrees; for experienced alpine climbers
Sustained hard rock and/or ice or snow; fairly serious stuff.
TD: Tres Difficile/very difficult.
Long, serious, remote, and highly technical.
ED: Extremement Difficile/extremely difficult.
The most serious climbs with the most continuous difficulties.