How was the western cordillera formed?

The Western Cordillera was formed primarily due to the tectonic activity associated with the collision of the North American Plate with the Pacific Plate and other smaller plates. This collision, which began around 200 million years ago, led to the uplift and folding of sedimentary rocks, creating the mountain ranges we see today, including the Rockies and the Sierra Nevada. Additionally, volcanic activity and erosion have shaped its current landscape over millions of years.