A photograph taken by my daughter of the lake (Lago Bianco) at Gavia Pass:
I think a part of the Forni glacier is visible.
Later: I realize that, as an Australian, I have not thought clearly about the definition of glacier. The glacier you see in the picture is probably the Dosegu glacier. If a glacier is the abstraction of water flow over the landscape (as I described a river in the last post about the Black Forest) the extent of the glacier is all that ice which flows together to a stream. The Forni glacier flows into the Frodolfo whereas the ice you see flows first into the Gavia which then joins the Frodolfo, a tributary of the Adda, which is itself a tributary of the Po.