The Pacific Ranges are another grab-bag super-range that contains the north-south trending ranges on the western rim of North America. Included are the major chains of the Coast Mountains, the Cascade Range, the Sierra Nevada, and the mountains of Baja California.
The arbitrary northern boundary of the Pacific Ranges is White Pass near Skagway, Alaksa, beyond which the mountains get a lot higher, icier, and colder in the form of the Saint Elias Mountains. Also, north of White Pass the mountains start trending east-west, instead of north-south.
The eastern edge of this mountain grouping is a largely indistinct line where the major Pacific chains like the Coast Mountains, the Cascade Range, and the Sierra Nevada merge into the less mountainous, dryer intermountain
terrain. This line is indistinct in B.C., follows U.S. highway 97 south into Washington and Oregon, and eventually U.S. 395 in California, and then meets the Colorado River near its delta to follow the Sea of Cortez south. The southern tip is, of course, Cabo San Lucas at the tip of Baja.
It seems pretty ludicrous to include the wide variety of ranges from Baja to southeast Alaska into one range, but there is a kind of structural unity to these mountains. For most of the length of this chain, there is a lower
coastal chain directly bordering the Pacific Ocean, a intervening valley, and then a higher, more inland chain behind that.
The lower coastal chain starts out as the Alexander Archipelago (the islands of southeast Alaska), and continues south as the Queen Charlotte Islands and Vancouver Island. It emerges entirely on land to stay as the Olympic Mountains and the Coast Ranges of Oregon and California. The intermediate valley begins as the Inside Passage, continues as Puget Sound and the Willamette Valley, and ends up as the Central Valley of California. The higher, eastern chain is the high wall formed by the Coast Mountains, Cascade Range, and Sierra Nevada.
In Southern California the lower and higher parallel chains merge into one complex range, which trends east-west as the Transverse Ranges before heading south as the Peninsular Ranges into Baja. While these ranges are dissimilar in some ways to those further north, the whole complex seemed like a logical unit, guarding the western edge of the continent like a series of ramparts.
Precipitation is very variable along the length of the Pacific Ranges. From Northern California northward, the mountains are among the wettest in the world, supporting temperate rain forests. The southern reaches of these ranges are more similar to the other ranges of the American west, with dry, open forests rising from dry desert plains.