LOCATION SNAHOPISH WAEstablished Series
TAXONOMIC CLASS: Medial-skeletal, mixed, isofrigid Pachic Fulvudands
TYPICAL PEDON: Snahopish very gravelly medial loam, forested. (Colors are for moist soil unless otherwise noted. All textures are apparent field textures.)
Oi--0 to 1 inch; slightly decomposed needles, leaves, and twigs.
A--1 to 11 inches; dark brown (10YR 3/3) very gravelly medial loam, yellowish brown (10YR 5/4) dry; moderate very fine and fine subangular blocky structure parting to granular; slightly hard, friable, sticky, plastic and weakly smeary; many very fine, fine and medium roots; many very fine and fine irregular and tubular pores; 30 percent angular pebbles and 10 percent angular cobbles; very strongly acid (pH 4.8); clear smooth boundary. (10 to 17 inches thick)
Bw1--11 to 22 inches; dark yellowish brown (10YR 4/6) very cobbly medial loam, light yellowish brown (10YR 6/4) dry; moderate very fine, fine and medium subangular blocky structure; slightly hard, friable, sticky, plastic and weakly smeary; many very fine and fine, and common medium roots; many fine and very fine irregular and tubular pores; 20 percent angular pebbles and 20 percent angular cobbles; very strongly acid (pH 4.8); gradual smooth boundary. (10 to 12 inches thick)
Bw2--22 to 42 inches; dark yellowish brown (10YR 4/6) very cobbly medial loam, light yellowish brown (10YR 6/4) dry; weak very fine, fine and medium angular blocky structure; slightly hard, friable, sticky, plastic and weakly smeary; common very fine and fine, and few medium roots; many very fine irregular, and many very fine and fine tubular pores; 30 percent angular pebbles and 20 percent angular cobbles; very strongly acid (pH 5.0); gradual smooth boundary. (12 to 20 inches thick)
Bw3--42 to 61 inches; dark yellowish brown (10YR 4/6) extremely cobbly medial loam, light yellowish brown (10YR 6/4) dry; massive; slightly hard, friable, sticky, plastic and weakly smeary; common very fine and fine roots; common very fine and fine irregular and tubular pores; 40 percent angular pebbles and 30 percent angular cobbles; very strongly acid (pH 5.0).
TYPE LOCATION: Clallam County, Washington; 200 feet south and 300 feet west of the northeast corner of section 7, T.29N., R.12W.
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 43 to 47 degrees F. The mean summer soil temperature is 47 to 50 degrees F and the mean winter soil temperature is 40 to 45 degrees F. The difference between the mean summer and winter soil temperature is 5 to 9 degrees F. These soils are usually moist and are dry 0 to 30 consecutive days in the summer; udic soil moisture regime. Depth to bedrock is over 60 inches. The particle-size control section from the mineral soil surface to bedrock contact has andic soil properties with 35 to 85 percent rock fragments by volume. The andic soil material has an estimated moist bulk density of 0.30 to 0.70 g/cc, acid-oxalate extractable aluminum plus one-half of the acid oxalate extractable iron of 2 to 5 percent, phosphate retention of 85 to 100 percent, 15-bar water retention of 25 to 50 percent for air-dried samples and acid oxalate iron of 1.0 to 2.5 percent. It has 2 to 8 cmol/kg of aluminum. The particle-size control section has 10 to 25 percent field estimated clay and 10 to 30 percent sand.
The A horizon has hue of 7.5YR or 10YR, value of 2 or 3 moist, 4 or 5 dry, and chroma of 2 through 4. This horizon has granular, subangular blocky or angular blocky structure. It has 15 to 40 percent organic matter.
The Bw1 and Bw2 horizons have hue of 7.5YR or 10YR, value of 3 through 5 moist, 4 through 6 dry, and chroma of 3 through 6 moist, and 3 or 4 dry. It is extremely gravelly medial loam, very cobbly medial loam, extremely cobbly medial loam, extremely gravelly medial silt loam, very cobbly medial loam, extremely cobbly medial loam, and extremely cobbly medial silt loam. It has 7 to 20 percent organic matter.
The Bw3 horizon has hue of 10YR or 2.5Y, value of 4 through 6 moist, 5 through 7 dry, and chroma of 4 or 6. It is very gravelly medial loam, very cobbly medial loam, extremely cobbly medial loam, and extremely cobbly medial silt loam. It has 4 to 7 percent organic matter.
COMPETING SERIES: These are the
Hookbranch,
Itswoot,
Lunchcreek, and Sollecks series. Hookbranch and
Solleks soils are 20 to 40 inches
deep to bedrock. Lunchcreek soils have a perudic soil moisture regime. Itswoot soils formed in glacial till and have rounded fragments.
GEOGRAPHIC SETTING: Snahopish soils are on mountain sides and foot slopes at elevations of 600 to 2,800 feet. They formed in residuum and colluvium from sandstone and loess. The soils are in a mild marine climate and have cool, moist summers and cool, wet winters. The mean annual precipitation is 100 to 170 inches. The average January temperature is about 37 degrees F.; the average July temperature is about 58 degrees F.; and the mean annual temperature is about 41 to 45 degrees F. The frost free season is 120 to 140 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Calawah, Ozette, and Tealwhit soils and the competing Solleks soils. Calawah and Ozette soils are medial. Tealwhit soils are fine and have an aquic moisture regime.
DRAINAGE AND PERMEABILITY: Well drained; medium runoff; moderate permeability.
USE AND VEGETATION: Timber production is the principal use. Native vegetation is predominantly western hemlock with Pacific silver fir. Understory species include salmonberry, red huckleberry, salal, vine maple, Oregon oxalis, western swordfern, deer fern, ladyfern and trillium.
DISTRIBUTION AND EXTENT: Western slopes of the Olympic Mountains, Washington; MLRA 4A. This series is moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Jefferson County, Washington, 1971.
REMARKS: Diagnostic horizons and other features are:
- Umbric epipedon - 1 to 11 inches
- Cambic horizon - 11 to 61 inches
- All depths to diagnostic horizons and other features are measured from the top of the first mineral horizon.
ADDITIONAL DATA: NSSL S89WA-031-002.