1000m, 37 pitches. Guidebook time 12 to 16 hours. 2 days is quite realistic.
Realy impressive N face. Important is the amount of ice on the icefield in 2/3 height. Till there it's excellent granit up to f6a. About 16 pitches. During the day stones will fall from the upper icefield, but the wall is steep, so the stones will stay clear of the wall. In 2003 we bivacked under a small overhang where the wall gets less steep. Next morning we climbed 2 pitches grad 4. Next with crampons over ice; a small vertical wall and then the top icefield witch leads to the right to the arete West. Follow this 7 more pitches to the summit. Don't follow the direct exit through the north face! Very bad gneiss there!
The way down on the South side is complicated and takes another 3,5 hours to the glacier and 1,5 hrs more to the Pelvoux hut. I will make another entry for the descent.