LOCATION CHRISTOFF WAEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, frigid Vitrandic Hapludalfs
TYPICAL PEDON: Christoff sandy loam - in a clearcut area on a 35 percent southwest-facing convex slope at an elevation of 2,000 feet. The soil was moist when described. (Colors are for moist soil unless otherwise noted. All textures are apparent field textures.)
Oi--0 to 1/2 inch; slightly decomposed leaves, needles, and twigs; abrupt
smooth boundary. (1/2 to 2 inches thick)
Oe--1/2 to 1 inch; moderately decomposed organic litter; abrupt
smooth boundary. (1/2 to 0 inch thick)
A--1 to 4 inches; very dark grayish brown (10YR 3/2)
ashy sandy loam, brown (10YR 5/3) dry; single gain; loose; many very fine, fine and common medium roots; 2 percent pebbles and 3 percent hard weathered cinders; strongly acid (pH 5.4); clear smooth boundary. (3 to 7 inches thick)
E1--4 to 13 inches; brown (10YR 4/3) ashy sandy loam (volcanic ash), very pale brown (10YR 7/3) dry; weak fine subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; very fine, fine, common medium and coarse roots; 5 percent pebbles and 5 percent hard weathered cinders; moderately acid (pH 5.6); clear smooth boundary. (5 to 9 inches thick)
2E2--13 to 27 inches; dark yellowish brown (10YR 4/4) loam, very pale brown (10YR 7/3) dry; weak medium subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; common very fine, fine, medium, and coarse roots; 10 percent pebbles; moderately acid (pH 5.8); clear wavy boundary. (5 to 14 inches thick)
2Bt1--27 to 43 inches; dark yellowish brown (10YR 4/4) loam, light yellowish brown (10YR 6/4) dry; weak medium subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; few very fine and firm roots; 5 percent pebbles; moderately acid (pH 5.8); gradual smooth boundary. (12 to 22 inches thick)
2Bt2--43 to 61 inches; brown (10YR 4/3) clay loam, pale brown (10YR 6/3) dry; weak coarse subangular blocky structure; hard, friable, moderately sticky and moderately plastic; 10 percent pebbles, common thin clay films in pores and on faces of peds; moderately acid (pH 5.8).
TYPE LOCATION: Snoqualmie Pass Area, King County, Washington; about 1/2 mile north of Greenwater; 1,400 feet north and 2,000 feet west of the southeast corner sec. 3, T. 19 N., R. 9 E.
RANGE IN CHARACTERISTICS: Mean annual soil temperature ranges from 44 to 47 degrees F. These soils are usually moist and are dry for less than 45 consecutive days following summer solstice. The particle-size control section averages 25 to 35 percent clay and 5 to 15 percent hard rock fragments.
The A horizon has value of 3 or 4 moist, and chroma of 2 through 4 moist or dry. Reaction is strongly acid or moderately acid.
The E horizon has hue of 7.5YR or 10YR, value of 4 or 5 moist, 7 or 8 dry, and chroma of 3 or 4 moist or dry. It is ashy sandy loam, gravelly ashy sandy loam, ashy loam, or gravelly ashy loam and is greater than 60 percent volcanic ash and cinders combined. It contains 5 to 10 percent hard weathered cinders and 5 to 20 percent pebbles.
The 2E horizon has value of 4 or 5 moist, 7 or 8 dry and chroma of 3 or 4 moist. It contains 5 to 15 percent pebbles.
The 2Bt horizon has value of 4 or 5 moist and chroma of 3 through 6 moist or dry. It is loam or clay loam and contains 5 to 15 percent pebbles. It is highly weathered breccia exhibiting rock structure and the weathered pebbles causes a mottled appearance. Some pedons have redox features with hue of 7.5YR or 10YR and chroma of 1 through 3 moist.
COMPETING SERIES: This is the Bechtel series. Bechtel soils have an albic horizon above the argillic horizon.
GEOGRAPHIC SETTING: Christoff soils are on mountain sideslopes and slump areas at elevations of 1,600 to 2,800 feet. Slopes range from 6 to 65 percent. Christoff soils formed in volcanic ash and cinders overlying highly weathered breccia and tuffaceous material. The climate is maritime with cool, dry summers and mild, wet winters. The mean annual precipitation ranges from 55 to 80 inches, occurring mostly as snowfall and rainfall during winter. Mean January temperature is about 31 degrees F, mean July temperature is about 60 degrees F, and the mean annual air temperature is about 44 degrees F. The frost-free season is 130 to 160 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Littlejohn, Ogarty and Pitcher soils. Littlejohn soils have bedrock within 20 to 40 inches of the surface. Ogarty soils are mesic. Pitcher soils are medial-skeletal.
DRAINAGE AND PERMEABILITY: Moderately well drained, medium runoff, moderately slow permeability. This soil has a water table as high as 2.5 to 4 feet at times from December through April.
USE AND VEGETATION: Used for timber production, wildlife habitat and watershed. Vegetation is Douglas-fir, western hemlock, and red alder with an understory of vine maple, western swordfern, red huckleberry, trillium, creambush oceanspray, salal, Oregon-grape, and western brackenfern.
DISTRIBUTION AND EXTENT: West slopes of the Cascade Mountains in west central Washington; MLRA 3. 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 area an ochric epipedon, an albic horizon from 4 to 27 inches, and an argillic horizon from 27 to 61 inches.