A helicopter flies over a segment of the Planpincieux glacier on the Italian side of the Mont Blanc massif area of Planpincieux, Aosta, Italy, September 25, 2019. Aerial footage released on Wednesday (September 25) showed a section of the Planpincieux glacier on Mont Blanc massif and estimated to contain up to 250,000 cubic metres of ice that experts believe could fall down the mountain. REUTERS/Flavio Lo Scalzo

A helicopter flies over a segment of the Planpincieux glacier on the Italian side of the Mont Blanc massif area of Planpincieux, Aosta, Italy, September 25, 2019. The mayor of the nearby town of Courmayeur, Stefano Miserocchi, ordered the closing of two roads and the evacuation of huts on the mountain, which is 4,800 metres (5,250 yards) high. REUTERS/Flavio Lo Scalzo

A segment of the Planpincieux glacier is seen on the Italian side of the Mont Blanc massif area of Planpincieux, Aosta, Italy, September 25, 2019. Between the end of August and the beginning of September the lower part of the glacier was sliding at a speed of 50-60 cm (20-24 inches) per day. REUTERS/Flavio Lo Scalzo

A helicopter flies over a segment of the Planpincieux glacier on the Italian side of the Mont Blanc massif area of Planpincieux, Aosta, Italy, September 25, 2019. The rise of global temperatures due to global warming is causing mountain glaciers to melt and the retreat of polar ice sheets. REUTERS/Flavio Lo Scalzo

A segment of the Planpincieux glacier is seen on the Italian side of the Mont Blanc massif area of Planpincieux, Aosta, Italy, September 26, 2019. The problem is affecting the Mont Blanc massif, Western Europe's highest mountain range, containing eleven major independent peaks, each over 4,000 metres in height. REUTERS/Yara Nardi

A segment of the Planpincieux glacier is seen on the Italian side of the Mont Blanc massif area of Planpincieux, Aosta, Italy, September 26, 2019. REUTERS/Yara Nardi