LOCATION INDEX WAEstablished Series
TAXONOMIC CLASS: Ashy-skeletal over sandy or sandy-skeletal, amorphic over isotic Andic Haplocryods
TYPICAL PEDON: Index ashy loamy sand - forested (Color is for moist soil unless otherwise stated. All textures are apparent field textures.)
Oi--0 to 1 inch; slightly decomposed forest litter, needles, twigs, bark and moss. (1 to 3 inches thick)
Oa--1 to 3 inches; black (10YR 2/1) highly decomposed organic matter that is bound by roots; abrupt smooth boundary. (0.5 to 3 inches thick)
E--3 to 5 inches; gray (10YR 5/1) ashy loamy sand (volcanic ash), light gray (7.5YR 7/1) dry; weak moderate subangular blocky structure; soft, very friable, nonsticky and nonplastic; many very fine roots; very strongly acid (pH 4.8); abrupt wavy boundary. (1 to 4 inches thick)
Bhs--5 to 7 inches; dark reddish brown (5YR 3/3) ashy sandy loam (volcanic ash), brown (7.5YR 4/4) dry; weak fine subangular blocky structure; slightly hard, firm, slightly sticky and nonplastic; many very fine and fine and few medium and coarse roots; moderately acid (pH 6.0); abrupt wavy boundary. (2 to 4 inches thick)
Bs1--7 to 10 inches; variegated reddish brown (5YR 4/4) and light gray (2.5Y 7/2) loamy sand (volcanic ash), variegated yellowish red (5YR 5/6) and pale yellow (2.5Y 8/2) dry; weak fine subangular blocky structure; slightly hard, friable, nonsticky and nonplastic; many very fine and fine and few medium and coarse roots; moderately acid (pH 5.6); abrupt irregular boundary. (2 to 5 inches thick)
Bs2--10 to 18 inches; brown (7.5YR 4/4) very cobbly ashy loamy sand, brown (7.5YR 5/4) dry; weak fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine and fine and few medium and coarse roots; 15 percent gravel and 25 percent cobbles; strongly acid (pH 5.4); clear smooth boundary. (6 to 12 inches thick)
2BC--18 to 26 inches; dark yellowish brown (10YR 4/4) very gravelly loamy sand; strong brown (7.5YR 5/6) dry; massive; soft, very friable, nonsticky and nonplastic; common very fine and fine and few moderate and coarse roots; 30 percent gravel, 20 percent cobbles; moderately acid (pH 5.8) clear smooth boundary. (6 to 15 inches)
2C1--26 to 43 inches; light yellowish brown (10YR 6/4) very cobbly sand; very pale brown (10YR 7/4) dry; massive; slightly hard, very friable, nonsticky and nonplastic; common very fine and fine roots; 25 percent gravel; 40 percent cobbles; strongly acid (pH 5.4); gradual smooth boundary. (15 to 35 inches thick)
2C2--43 to 60 inches; pale yellow (2.5Y 7/4) extremely cobbly sand; light yellowish brown (10YR 6/4) dry; massive; slightly hard, very friable, nonsticky and nonplastic; 35 percent gravel, 30 percent cobbles; strongly acid (pH 5.4); clear smooth boundary. (5 to 20 inches thick)
2Cr--60 inches; yellowish brown (10YR 5/6) highly weathered granodiorite; very pale brown (10YR 8/4) dry;this material can be cut with a spade with difficulty and texture is very gravelly coarse sand; 60 percent hard gravel; slightly acid (pH 6.2).
TYPE LOCATION: Snoqualmie Pass Area, King County, Washington; on east side of Hansen Creek drainage, about 100 feet east of Forest Service Road number 2291.1; 2,300 feet south and 1,800 feet west of the northeast corner of sec. 22, T. 22 N., R. 10 E.
RANGE IN CHARACTERISTICS: Depth to the paralithic contact is 40 to 70 inches. Rock fragments, including hard cinders in the particle-size control section, average from 35 to 70 percent by volume. The mean annual soil temperature is 42 to 46 degrees F. Depth to the lithologic discontinuity is 14 to 25 inches.
The E horizon has hue of 10YR or 7.5YR, value of 5 through 7 moist and 6 or 7 dry, and chroma of 0 through 2 moist or dry. Reaction is moderately acid to very strongly acid. There is tonguing of this horizon into the Bhs horizon in some pedons.
The Bhs horizon has value of 3 through 5 moist and 4 or 5 dry, and chroma of 3 through 6 moist or dry. Structure grades from weak to strong. Reaction is moderately acid to very strongly acid.
The Bs horizon has hue of 2.5Y to 5YR. Hues of 10YR to 5YR have value of 3 or 4 moist, 4 or 5 dry and chroma of 4 to 6 moist and dry. Where present, the hues of 2.5Y have value of 6 to 8 moist, 7 or 8 dry, and chroma of 2 or 3. Texture is ashy sand or ashy loamy sand with 30 to 60 percent rock fragments in the lower part. The fine-earth fraction is more than 60 percent volcanic ash and pumice. Reaction is moderately acid or strongly acid.
The 2BC horizon has hue of 7.5YR or 10YR, value of 4 or 5, and chroma of 4 through 6 moist or dry. The texture of the fine-earth fraction is loamy sand or sand. Coarse fragments range from 40 to 60 percent by volume. The structure ranges from massive, exhibiting some rock structure, to a moderate expression of subangular blocky structure. Reaction is moderately acid to strongly acid.
The 2C horizon has hue of 10YR or 2.5YR, value of 6 or 7 moist and dry, and chroma of 4 moist and dry. Coarse fragments range from 50 to 70 percent by volume. The horizon is massive exhibiting some rock structure. Some pedons have weak, fine subangular blocky structure. Coarse fragments are residual rock fragments. Reaction is moderately acid or strongly acid.
The bedrock is granitic rock, or low grade metamorphic rock such as slate or phyllite.
COMPETING SERIES: These are the Altapeak, Serene and Skipeak series. Serene series are 20 to 40 inches deep to a paralithic contact. Skipeak soils are very deep and have rounded rock fragments of mixed lithology in the particle-size control section. Altapeak soils have a mean annual soil temperature of 37 to 42 degrees F.
GEOGRAPHIC SETTING: Index soils are on mountain slopes at elevations of 2,200 to 3,600 feet. The lower limit of the elevation range is on northerly and easterly exposures and in cold air drainages. Slopes range from 8 to 90 percent. Index soils formed in a thin mantle of volcanic ash over residuum and colluvium from granitic and low grade metamorphic rocks. The climate is maritime influenced with cold, wet winters, and cool, moist summers. The mean January temperature is about 27 degrees F; the mean July temperature is about 60 degrees F; mean annual air temperature is about 42 degrees F. Average annual precipitation is 75 to 110 inches, with a considerable portion of this being in the form of snow. Frost-free season is 110 to 130 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Altapeak and Serene soils and the Kindy, Klapatche, Marblemount, Nagrom, Playco, Reggad, and Teneriffe soils. Kindy, Klapatche, Nagrom and Marblemount soils are all 20 to 40 inches deep to a paralithic contact. The Marblemount and Teneriffe soils are frigid. Nagrom and Playco soils are loamy-skeletal. Reggad soils lack a spodic horizon and are fragmental.
DRAINAGE AND PERMEABILITY: Well drained, moderately rapid permeability, slow to medium runoff.
USE AND VEGETATION: Used for timber production, watershed, and, wildlife habitat. Vegetation is western hemlock, Douglas-fir, Pacific silver fir, noble fir, and Alaska yellow cedar with an understory of huckleberry, common beargrass, salal, longtube twinflower, bunchberry dogwood, and Oregongrape.
DISTRIBUTION AND EXTENT: Western slopes of the Cascade Mountains in west central Washington, MLRA 3. Series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Snoqualmie Pass Area, King County, Washington, 1986.
REMARKS: Partial laboratory data are available on these soils number S79WA033-004 and 80T7083-7085.
Diagnostic horizons and features recognized in this pedon are an albic horizon from 3 to 5 inches and a spodic horizon from 5 to 18 inches. These soils meet chemical requirements for a spodic horizon. The particle-size class was updated to ashy-skeletal over sandy or sandy-skeletal on 8/2007 due to addition of this class in the 10th edition of Keys to Soil Taxonomy.