Swinomish soils are dry for 75 to 90 consecutive days following summer solstice. Vanzandt soils are on glacially modified slopes and valleys at elevations of 250 to 1,500 feet. Slopes are 0 to 65 percent. These soils formed in volcanic ash and glacial till and slope alluvium and colluvium containing volcanic ash and glacial till. Summers are warm and dry.
Winters are cool and moist with intermittent snow cover.
Mean annual precipitation is 45 to 70 inches. The frost-free season is 140 to 180 days. These are the Barneston , Montborne , Rinker , and Sehome soils and the competing Heisler and Squires soils. Barneston soils are deep and are sandy-skeletal. Montborne and Rinker soils have a frigid temperature regime.