Another problem on the glacier is the disappearance of its tributaries. Many of its tributaries no longer meet it. This deprives the glacier of a significant portion of its former ice sources. The head of the glacier is fed by debris from the Kanchenjunga slopes. The lower 18 km of the glacier is an ablation zone where melting is immense. Recent studies have shown that between 2000 and 2013 the surrounding glaciers of the Zemu have shrunk drastically, reducing the source for the main glacier and increasing the risk of its shrinkage.