That looks like a big cornice on the summit of Vallunaraju
Fortunately, the true summit is just a bit further back, and a lot safer to reach. If you look closely, you can see the trail go to the lowest point on the ridge, well right of center. After crossing the bergschrund and a very short steep section, the trail continues on the other side of the ridge, well away from the dangerous drop.
14 June 2011.