The resolution of each attack emanating-from/resolved-in a Hill hex that contains a Drift counter must involve a third die. If the result on the third die is "6", an avalanche has been triggered. Move the Drift counter to the nearest lower elevation hex (in the event of equidistant lower elevation hexes, determine the affected one randomly). All units/SW/Guns/Fortifications in the hex to which the Drift is moved are immediately eliminated.