The Garden Wall is a perfect example of a glacial arete , formed when glaciers attack a ridge on each side. Melting, the glaciers leave a high, knife-edged wall. Chief Mountain was once part of a great rock mass. Erosion wore away much rock and today Chief Mountain stands isolated.
Erosion is at work constantly remaking the face of the mountains.
Water, wind, and ice break down the rock into smaller fragments that fall to the foot of the mountains. These piles of rock are called talus . Notice the trees that have taken a foothold on the slope in nature's continuing struggle. Waterton-Glacier's many trails provide access into a land little changed by man. Here two hikers, high above Waterton townsite, look south across Upper Waterton Lake toward Glacier NP in the distance.