LOCATION PHILIPPA WAEstablished Series
TAXONOMIC CLASS: Medial-skeletal, amorphic, frigid, ortstein Andic Durihumods
TYPICAL PEDON: Philippa sandy loam - on a northwest facing 23 percent slope under coniferous forest at 1,960 feet elevation. (Colors are for moist soil unless otherwise stated. All textures are apparent field textures. When described the soil was moist throughout)
Oi--2 to 1/2 inch; mosses, twigs, needles.
Oa--1/2 inch to 0; decomposed forest litter; abrupt smooth boundary.
A--0 to 3 inches; dark brown (7.5YR 3/2) sandy loam, brown (7.5YR 5/3) dry; weak very fine subangular blocky structure; soft, very friable, slightly sticky, slightly plastic, weakly smeary, many very fine and fine roots, common medium roots; many very fine interstitial pores; 5 percent subangular pebbles; very strongly acid (pH 4.6), NaF pH 9.6; abrupt smooth boundary. (0 to 4 inches thick)
E--3 to 4 inches; dark grayish brown (10YR 4/2) coarse sandy loam (volcanic ash), pinkish gray (7.5YR 6/2) dry; weak fine subangular blocky structure; soft, very friable, nonsticky, nonplastic, weakly smeary; common fine and medium roots; many very fine interstitial pores; 5 percent subangular pebbles; extremely acid (pH 4.0), NaF pH 9.6; abrupt smooth boundary. (Trace to 5 inches thick)
Bhs--4 to 9 inches; variegated dark reddish brown (5YR 3/3, 70 percent) and strong brown (7.5YR 4/6, 30 percent) gravelly silt loam, reddish brown (5YR 4/3) and reddish yellow (7.5YR 6/6) dry; moderate fine subangular blocky structure; slightly hard, very friable, slightly sticky, slightly plastic, moderately smeary; common fine and medium roots; common very fine interstitial pores; 15 percent subangular pebbles; very strongly acid (pH 4.8); NaF pH 12.0+; gradual wavy boundary. (3 to 9 inches thick)
Bs1--9 to 18 inches; dark brown (7.5YR 4/4) gravelly silt loam, reddish yellow (7.5YR 6/6) dry; moderate fine and very fine subangular blocky structure; slightly hard, very friable, slightly sticky, slightly plastic; moderately smeary; common fine roots; common very fine interstitial pores; 25 percent subangular pebbles; very strongly acid (pH 5.0); NaF pH 12.0+; clear smooth boundary. (7 to 15 inches thick)
Bs2--18 to 28 inches; dark yellowish brown (10YR 4/4) very gravelly sandy loam, yellowish brown (10YR 5/6) dry; weak medium subangular blocky structure; slightly hard, friable, slightly sticky, slightly plastic; moderately smeary; few very fine roots; common very fine interstitial pores; 45 percent subangular pebbles, 10 percent cobbles; very strongly acid (pH 5.0); NaF pH 12.0+; abrupt smooth boundary. (8 to 13 inches thick)
Bsm--28 to 60 inches; dark grayish brown (2.5Y 4/2) ortstein (cemented glacial till) that breaks to extremely gravelly loamy sand, light brownish gray (2.5Y 6/2) dry; common fine prominent dark reddish brown (5YR 3/3) and reddish brown (5YR 4/4) mottles; massive; extremely hard, extremely firm, nonsticky, nonplastic; 60 percent subangular pebbles, 10 percent cobbles; strongly acid (pH 5.4), NaF pH 12.0+.
TYPE LOCATION: Snoqualmie Pass Area, King County, Washington; along a spur road of the No. 50 Road; 800 feet south of the Tolt - Seattle Water Supply Reservoir; 2,600 feet east, 1,500 feet south of the northwest corner of sec. 34, T. 26 N., R. 9 E.
RANGE IN CHARACTERISTICS: Depth to the paralithic contact with dense glacial till ranges from 20 to 40 inches. The mean annual soil temperature is estimated to range from 44 to 46 degrees F. Rock fragments in the control section average from 35 to 50 percent by volume.
The A horizon has hue of 7.5YR or 10YR moist or dry, value of 4 or 5 dry, and chroma of 2 or 3 moist or dry. This horizon is absent in some pedons. Reaction is extremely acid or very strongly acid.
The E horizon has hue of 7.5YR or 10YR moist or dry, value of 4 or 5 moist, 6 or 7 dry, and chroma of 1 or 2 moist or dry. It is sandy loam or coarse sandy loam.
The Bhs horizon has hue of 7.5YR or 5YR moist or dry, matrix value of 4 or 5 dry, and matrix chroma of 2 or 3 moist or dry. It is silt loam, loam, gravelly silt loam or gravelly loam. Rock fragments range from 10 to 20 percent by volume.
The Bs horizon has chroma of 4 through 6 dry. Textures are gravelly loam, gravelly silt loam, or very gravelly loam. Rock fragments range from 20 to 40 percent by volume. Reaction is very strongly acid or strongly acid.
The Bs2 horizon has value of 5 or 6 dry, and chroma of 4 through 6 moist or dry. Textures are very gravelly loam, very gravelly sandy loam, extremely gravelly loam, or extremely gravelly sandy loam. Rock fragments range from 50 to 70 percent by volume. Reaction is very strongly acid or strongly acid.
The Bsm horizon has value of 4 or 5 moist, 6 or 7 dry. It is iron and organic matter cemented dense glacial till that breaks to extremely gravelly loamy sand or extremely gravelly loamy coarse sand. Rock fragments range from 60 to 80 percent by volume.
COMPETING SERIES: These are the Cupples, Kaleetan, Marblemount, Melakwa, Solduc, and Teneriffe soils in other families. Cupples, Solduc, Marblemount, and Teneriffe soils have in all subhorizons of the spodic horizon. In addition, Kaleetan, Solduc, and Teneriffe soils are greater than 40 inches deep. Marblemount and Melakwa soils have a lithic contact at 20 to 40 inches.
GEOGRAPHIC SETTING: Philippa soils are in cirques on lateral moraines in mountains. These soils formed in volcanic ash, colluvium, and ablation till over compact basal till. Source rock is predominately andesite, granodiorite, metasediments and metavolcanics. Slopes are 0 to 65 percent. Elevations range from 1,600 to 2,800 feet. The climate is marine influenced with relatively cool, dry summers and cool, wet winters. Average annual precipitation ranges from 90 to 140 inches. The mean January temperature is about 30 degrees F, mean July temperature is about 60 degrees F, and the mean annual temperature is about 44 degrees F. The frost-free season (32 degrees F) is 130 to 160 days. The growing season (28 degrees F) is 150 to 170 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Kindy, Shuksan, and Skykomish soils and the competing Marblemount and Teneriffe soils. Kindy and Shuksan soils are cryic. Skykomish soils are sandy-skeletal.
DRAINAGE AND PERMEABILITY: Moderately well drained; slow or medium runoff; permeability is moderate in the solum and very slow in the dense glacial till substratum. A perched water table occurs as high as 2 to 3 feet at times from December through March.
USE AND VEGETATION: Timber production, watershed and wildlife habitat are the principal uses. Overstory vegetation is Douglas-fir, western hemlock, western redcedar, and red alder. Understory vegetation includes salal, vine maple, western swordfern, devils club, salmonberry, red huckleberry and deer fern.
DISTRIBUTION AND EXTENT: West slopes of the northcentral Cascade Mountains in Washington. Series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Snoqualmie pass Area, King County, Washington, 1986.
REMARKS: Diagnostic horizons and features recognized in this pedon are an ochric epipedon from the mineral surface to 3 inches, a albic horizon from 3 to 4 inches, and a spodic horizon from 4 to 9 inches that is more than 6 percent organic carbon, a spodic from 4 to 18 inches that is assumed to meet chemical criteria for a spodic horizon, and a cemented spodic horizon (ortstein) at 28 inches.