5 - 6
FATMAP difficulty grade
You descend from the viaduct over the lake towards a boulder at the entrance to the vast Suretta gully, which you go up to the left of the stream (more or less covered with snow - be careful -) until you come out in an amphitheater of rocks (which slowly drain) .
From here, with a gradually more pronounced ascent - most recently with zigzag traverses - you reach the foot of the last gully; it can be reached by climbing as far as possible on the left shoulder and along it with narrow hairpins until the end of the difficulties.
Continue to the right on successive bumps until you reach the slight slope once occupied by the Suretta Glacier; with some mild ups and downs you get closer to the tip that houses the bivouac - visible -.
The last stretch, short but very steep and again zigzag, leads to reach the red building of Bivacco Suretta 2748 m from behind. Descent for the ascent route, very fast and fun.