Avalanche: various shots of men crossing snowy ravine on catwalk, moving up snow-covered slopes, digging at spot indicated by leader. Shot of army team installing large mortar in hole in preparation for blasting threatening snow accumulations. CU of men during pause. Broadside MS of two men stepping into snowmobile. Shot of Glacier National Park sign, FOLLOW SHOT of snowmobile heading for mountain. HASs of snowmobile moving across trackless strertches of snow, amidst snow-covered spruce and fir trees. Front HAS of CPR diesel train emerging from tunnel, passing close and below camera. Opposite angle shot of train moving away in mountain winter setting. Shot of army personnel chatting on platform at station, snowmobile waiting for them in background.