The invention concerns a device for provoking the collapse of a snow cornice comprising several exploders (11). Each exploder (11) consists of a main cylinder (12), perpendicular to the support base (14) arranged flat on the ground, and a positioning tube (13) connected to the main cylinder and mounted on a rigid seat (15) fixed to the mountain side. A supply conduit (20), connected by conduits (23, 24) respectively to an oxygen cylinder and a propane cylinder stored in a shelter (22), supplies via conduit sections (9) a detonating gas mixture, obtained from two gases, into the positioning tube (13) and into the main cylinder (12). Igniting means (21) mounted upstream of the supply conduit (20) ensure the ignition of the detonating gas mixture.