At Least 9, Maybe 13, Avy Fatalities Near Mt Blanc

Still very early for any solid news, but the grim count so far seems to be nine confirmed dead, another four missing, and eleven hospitalized.

Edit:
Accordingly to an apparently more recent report, the four previously unaccounted-for climbers are now safely accounted for.  (Two had taken a different route, and another two had cancelled their climb entirely.)

Route map below:




The initial account (and the map) is from the BBC.

But a more updated account from the Associated Press has this assessment of the slide mechanics:

A block of ice 40 centimeters (16 inches) thick broke off and slid down the slope, creating a mass of snow that was 2 meters (6 feet) deep and 50 meters (160 feet) long.
"The first elements that we have from testimony are that a climber could have set loose a sheet of ice, and that sheet then pulled down the group of climbers below. I should say the incline was very, very steep on this northern face," Col. Bertrand François of the Haute-Savoie police told reporters.