A snow-plough blade group for absorbing lateral impacts comprising: a first and a second snow-removing blade; a first support bearing the blades; the second blade being mobile with respect to the first support between a first position, in which the blades identify a first snow-removing surface, and a second position in which the blades identify a second snow-removing surface larger than the first one; a second support hinged to the first support; a first hydraulic cylinder connected between the first and second support for orientating the first support with respect to the second support; a discharge of liquid in overpressure; bypass valve means connecting the first hydraulic cylinder with the discharge, which bypass valve means are configured such that when the pressure in the first hydraulic cylinder exceeds a threshold value, the bypass valve means place the first hydraulic cylinder in liquid communication with the discharge; characterized in that a sensor detects a position assumed by the second blade; and the bypass valve means vary the threshold value according to the sensor reading.