On 16 October 2020, Italian authorities banned the access path to the Boccalatte-Piolti refuge (2,803 m or 9,196 ft) and to the Grandes Jorasses normal route (4,208 m or 13,805 ft).
The reason for banning the access to the Grandes Jorasses normal route was the growing risk of part of the Whymper serac collapsing.
24 hours after the decree was enforced, a large block of ice broke away from the Whymper serac.
During the night of Saturday 17 to Sunday 18 October, 15,000 m3 (529,720 ft3) of ice broke off from the Whymper serac located at an altitude of nearly 4,000 m (13,123 ft) in the Italian part of the Mont-Blanc massif.
Readings on 19 October showed that the ice avalanche stopped at about 2,700 m (8,858 ft) altitude below in the south face of the Grandes Jorasses.
The Grandes Jorasses glacier has been the subject of increased vigilance for more than 20 years. Even if it does not directly threaten the homes of Val Ferret, the serac Whymper remains a danger for the routes and races passing below. The decree, therefore, remains in force until further notice.
Source @Le Dauphine