We gonna take an average slope, like a blue run down here.

我们将要选择一个中级水平的雪道，就像这个蓝道（中级道）一样。

A few miles to the westward, this moraine has an average slope of twenty-seven degrees, and an elevation above the bottom of the channel of six hundred and sixty feet.

向西几英里处，这个冰碛的平均坡度为 27 度，高于河道底部 660 英尺。