Region 5: The Pacific Border

The Pacific Border Region has a notable range of soil orders because of its varied topography, nearby volcanism, coastal processes, and the past glaciation of its northern areas. High-energy beaches in the north and lower-energy beaches in the south provide a range of sediments for soil building. Soil material is also contributed by streams descending from the mountains, which create unique fluvial deposits. An amazing history of chaotic events, including repeated glaciations during the Pleistocene, the Missoula Floods, and the Columbia River Flood Basalts, have all left their mark on the coast. All of the dominant soil types previously discussed can be found in this region due to the variance in climate, vegetation, and geology that exists from north to south. Andisols are found mostly along the Washington coast, Inceptisols cover the coasts of Oregon and northern California, and Mollisols are scattered around the rest of California’s coast.