Confluence of the Sauk and Skagit Rivers, near Rockport.

The Skagit River Watershed’s Geologic Evolution

Join North Cascades Institute and Jon Reidel on June 8 for a class on the "Geologic Evolution of the Skagit River Watershed." Led by the acclaimed retired North Cascades National Park geologist, this new Field Excursion explores how the Skagit River Watershed developed over the past several million years. An epic series of events — including glaciation, landslides, and volcanic eruptions — have shaped the nature of the region we know and love today, and together we'll seek out evidence of it's tumultuous history along the North Cascades Highway. Info and registration at

By Dr. Jon Riedel

The Skagit River is the heart and soul of the North Cascades. It is by far the largest watershed in the southern arms of the Salish Sea, draining an area of topographic riddles and complex geology.

I have been a student of the Skagit’s natural history since I first set eyes on the valley in 1980. My focus as a geologist for the past 44 years has been writing the glacial chapters of the geologic story of the Skagit River watershed. I am offering a Field Excursion on June 8 with the North Cascades Institute that will allow me to share some of the Skagit’s remarkable geologic stories at five key sites between Diablo and Concrete. Along the way, I’ll relate how these changes influenced the natural history of the watershed, from salmon to rhododendrons to fields.

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