Leaving this place, I walked across the range to look at a fire that was burning beyond the bounds of the snowfall. It was in a heavily forested cove and was rapidly undoing the constructive work of centuries. This cove was a horseshoe-shaped one and apparently would hold the fire within its rocky ridges. While following along one of these ridges, I came to a narrow, tree-dotted pass, the only break in the confining rocky barrier. As I looked at the fire down in the cove, it was plain that with a high wind the fire would storm this pass and break into a heavily forested alpine realm beyond. In one day two men with axes could have made this pass impregnable to the assaults of any fire, no matter how swift the wind ally; but men were not then defending our forests and an ill wind was blowing. Many factors help to determine the speed of these fires, and a number of observations showed that under average conditions a fire burned down a slope at about one mile an hour; on the level it traveled from two to eight miles an hour, while up a slope it made from eight to twelve. For short distances fires occasionally roared along at a speed of fifty or sixty miles an hour and made a terrible gale of flames. I hurried up into the alpine realm and after half an hour scaled a promontory and looked back to the pass. A great cloud of smoke was streaming up just beyond and after a minute tattered sheets of flame were shooting high above it. Presently a tornado of smoke and flame surged into the pass and for some seconds nothing could be seen. As this cleared, a succession of tongues and sheets of flame tried to reach over into the forest on the other side of the pass, but finally gave it up. Just as I was beginning to feel that the forest around me was safe, a smoke-column arose among the trees by the pass. Probably during the first assault of the flames a fiery dart had been hurled across the pass. Up the shallow forested valley below me came the flames, an inverted Niagara of red and yellow, with flying spray of black. It sent forward a succession of short-lived whirlwinds that went to pieces explosively, hurling sparks and blazing bark far and high. During one of its wilder displays the fire rolled forward, an enormous horizontal whirl of flame, and then, with thunder and roar, the molten flames swept upward into a wall of fire; this tore to pieces, collapsed, and fell forward in fiery disappearing clouds. With amazing quickness the splendid hanging garden on the terraced heights was crushed and blackened. By my promontory went this magnificent zigzag surging front of flame, blowing the heavens full of sparks and smoke and flinging enormous fiery rockets. Swift and slow, loud and low, swelling and vanishing, it sang its eloquent death song.