Most weather fronts originating in the Pacific Ocean travel east toward the Cascade Mountains.

[6] Geological events occurring many years ago created the diverse topography and drastic elevation changes over the Cascade Range leading to the various climate differences.

Snowgrass Mountain is composed of schist, part of the Nason terrane laid down 210 million years ago.

[7] During the Pleistocene period dating back over two million years ago, glaciation advancing and retreating repeatedly scoured the landscape leaving deposits of rock debris.

Uplift and faulting in combination with glaciation have been the dominant processes which have created the tall peaks and deep valleys of the Alpine Lakes Wilderness area.