On the morning of Tuesday 16 August 2016, at about 5am, three climbers were clambing the Trois Monts route to the summit of Mont-Blanc (4,809m).
According to the Dauphiné Libere, the climbers were at about 4,100 meters, approaching the Col du Mount Maudit (4,465m). They were passing below a large outcrop of seracs. A serac is a large block of ice, that might be as big as a small house.
Several seracs broke away from the ice pack and triggered a slab avalanche that descended rapidly towards the climbers. The three victims suffered major traumatic shock, that was fatal.
The victims were a male, High Mountain Guide (50) of German nationality, resident of Lavancher, Chamonix, since 2015. The High Mountain Guide was accompanied by two clients, a Slovak woman (32) and an Anglo-Polish woman (33).
The mountain guide and his clients departed from Chamonix, on the afternoon of the 15 August, ascended to the summit of the Aiguille du Midi on the telepherique, and they climb down the arret and traversed to the Cosmiques refuge (3,613 meters), Tuesday morning, at about 1:15am, they departed from the refuge and continued their itinerary by way of the Trois Monts.
According BFM.TV, the Chamonix PGHM was alerted on Wednesday, 17 August, at about 6:30pm by a friend of the guide, who was anxious that they had not returned. Lieutenant Colonel Stéphane Bozon, commander of PGHM in Chamonix "We were alerted early about an avalanche, but the information provided from mountain guides and climbers in the area, led the PGHM to believe that no one had been buried in the avalanche".
According to Le Figaro, eight gendarmes with at least two dogs were dispatched at 20:08hrs, (probably using two helicopters) to the site of the avalanche. The dogs started to search and very quickly by 20:50hrs they had discovered the bodies of two women.
According to France 3, the PGHM Chamonix rescue service found the two women bodies Wednesday night, between 6:30pm and 10:30pm. The mountain guide body was found the following morning, Thursday 18 August at about 6:30am.
According to the Dauphiné Libere, they were buried in avalanche debris, between 50 centimeters and one meter.
All three victims had suffered fatal head trauma, that was probably inflected in the initial impact of the serac and slab avalanche. Death would have been almost instant. Their bodies were carried down the slope for at least 150 meters distance in the avalanche that consisted of seracs, slab and snow.
According to the Press release of Ministry of Interior, an investigation has been opened by the prosecutor of Bonneville to determine the circumstances of the accident. The investigation was assigned to Chamonix PGHM.