Belle and Queets soils have a cambic horizon and a udic moisture regime. The Sultan series are in the parts of river valleys that have slightly undulating microrelief at elevations ranging from near sea level to 120 feet. They formed in stratified loamy alluvium. The climate is marine. The average annual precipitation ranges from 35 to 55 inches and most of it falls as rain during winter.
Snow is infrequent.
The frost-free season ranges from 150 to 200 days. These are the Nooksack , Pilchuck , Puget , Puyallup , and Woodinville soils. Nooksack soils are coarse-silty and have a mollic epipedon. Pilchuck soils are sandy. Woodinville soils have an aquic moisture regime and thin lenses of organic material within the series control section.