Alta’s fabulous terrain, deep snow and light powder are no coincidence. They are the result of a fundamental geologic mechanism that has shaped this environment for millions of years. The Wasatch Fault is one of the most dramatic high-angle faults in the world. Over time, movement along this fault created the Wasatch Mountains. By our time frame this process is slow; in geologic terms the pace is blistering.

During the Wisconsin Glaciation the Wasatch Mountains trapped precipitation in such quantities in the winter that snow remained throughout the year and glaciers formed. These glaciers carved Alta’s distinctive terrain, broad U-shaped valleys, dramatic headwalls, hanging valleys, and steep gulleys. Today the Wasatch Mountains are the first major barrier to storms east of the Sierra Nevada Range. As Pacific storms cross the high desert of Nevada they grow colder and release their moisture as light, fluffy powder on the glacier-groomed slopes of Alta Ski Area, producing some of the finest skiing in the world. The geometry of Little Cottonwood Canyon with Alta at the mountain divide captures every possible flake of snow from passing storms and the “lake effect” of the Great Salt Lake adds to snow totals. The steep north-facing glacial headwalls of Mt. Baldy, Devils Castle and Sugarloaf Peak shade much of the area from sunshine preserving snow quality through much of the winter. All of these features combine to make the foundation of the totally unique Alta experience.

In this section of the Alta Historical Society’s web page we explore the geology of Alta as it affects the shaping of the land and the skiing experience. We describe the bed rock geology, structural geology and glacial history and relate all of these to twenty of the most famous and popular ski runs at Alta. The idea is to make your next ski trip to Alta a little more interesting, if such a thing is possible. At the very least you will leave here with a better understanding of what underlies the Greatest Snow on Earth.

This geology section was created by Brian K. Jones, consulting geologist and outdoor writer.