While I’m a global warming skeptic too, it is true that the glaciers of the Alps have shrunk considerably over the last 100 years or so. (I think this is one big reason Europe is so believing of global warming—as they (think) they see it in the Alps very clearly (even as glaciers in other parts of the world grow...). Climate change of course is normal...and I don’t think we know the size of the glaciers in the Alps during the medieval warming period, ca. AD 1000.
I believe this ammo was left on TOP of the glacier in 1915, and was subsequently covered up, and frozen into it—only now being revealed as the end of the glacier melts and recedes. Point being the ammo wasn’t gathered up by the glacier-growing flowing down the valley.
While few remember it now (as these didn’t involve Americans, French or English), some very fierce battles of WWI occurred high-up in the Alps...