The West Crater-Soda Peaks zone covers an area of , to the southeast of Mount St. Helens. A monogenetic volcanic field, it consists of 13 basaltic to andesitic volcanic edifices that vary from 360,000 years old to 2,000 years old. They appear as a series of isolated lava flows emplaced as single units, except for the deposits at Bare Mountain, South Soda Peaks, and West Crater where deposits are more complex.