LOCATION THOW WAEstablished Series
TAXONOMIC CLASS: Ashy, glassy, frigid Typic Vitrixerands
TYPICAL PEDON: Thow paragravelly ashy fine sandy loam, under coniferous forest, with grasses and shrubs on a 40 percent north facing slope at an elevation of 2,300 feet. (Colors are for dry soil unless otherwise stated. All textures are apparent field textures).
Oi--0 to 1 inch; undecomposed forest litter.
A--1 to 9 inches; light brownish gray (10YR 6/2) paragravelly ashy fine sandy loam, very dark grayish brown (10YR 3/2) moist; weak large crumb structure; soft, very friable, nonsticky and nonplastic; many very fine roots; many fine tubular pores; 1 percent gravel and 15 percent pumice paragravel; slightly acid (pH 6.2); clear smooth boundary. (6 to 10 inches thick)
Bw--9 to 23 inches; pale brown (10YR 6/3) paragravelly ashy sandy loam, dark brown (10YR 3/3) moist, weak medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; many very fine and medium roots; common fine tubular pores; 5 percent gravel and 15 percent pumice paragravel; slightly acid (pH 6.4); gradual wavy boundary. (10 to 50 inches thick)
BC--23 to 43 inches; light gray (10YR 7/2) paragravelly ashy coarse sandy loam, dark grayish brown (10YR 4/2) moist; weak large subangular blocky structure; soft, very friable, nonsticky and nonplastic; common medium roots; many large tubular pores; 10 percent gravel and 15 percent pumice paragravel; slightly acid (pH 6.4) gradual wavy boundary (0 to 16 inches thick)
2C--43 to 61 inches; light gray (10YR 7/2) extremely cobbly loamy sand; dark grayish brown (10YR 4/2) moist; single grain; soft, very friable, nonsticky and nonplastic; few fine and medium roots; common medium tubular pores; 40 percent gravel, 25 percent cobbles and 10 percent stones; neutral (pH 6.8)
TYPE LOCATION: Chelan County, Washington; 7 miles west of Chelan, Washington; 1,150 feet south and 800 feet west of northeast corner sec. 14, T. 27 N., R. 21 E.
RANGE IN CHARACTERISTICS: These soils are usually moist but are dry in all parts for 60 to 90 consecutive days after the summer solstice. The mean annual soil temperature is 42 to 46 degrees F. The particle-size control section has an estimated moist bulk density of 0.65 to 1.00 g/cc, volcanic glass content of 30 to 60 percent including 5 to 35 percent pumice 2 mm to 10 mm in diameter, acid-oxalate extractable aluminum plus one-half of the acid-oxalate extractable iron of 1.0 to 2.0 percent and 15-bar water retention of 5 to 12 percent for air dried samples. Depth to the 2C horizon is 40 to 80 inches. Reaction is slightly acid to neutral.
The A horizon has value of 5 through 7 dry and 3 to 4 moist, and chroma of 2 through 4 dry and 2 through 4 moist. Some pedons have a thin discontinuous C horizon having value of 6 to 8 dry, 4 to 6 moist and chroma of 1 to 3 dry or moist. This C horizon is assumed to be a relatively fresh deposit of Glacier Peak ash.
The Bw horizon has value of 5 through 7 dry, and 3 to 5 moist, and chroma is 1 through 4 dry and 2 through 4 moist. Texture is paragravelly ashy sandy loam or paragravelly ashy fine sandy loam.
The BC horizon has value of 5 through 7 dry, and 3 to 5 moist, and chroma of 2 through 4 moist or dry. Texture is paragravelly ashy coarse sandy loam, paragravelly ashy sandy loam, or paragravelly ashy fine sandy loam.
The 2C horizon has value of 6 or 7 dry, and 4 or 5 moist, and chroma of 2 or 3 dry or most. Texture is extremely cobbly loamy sand, very gravelly coarse sandy loam, or very gravelly loamy coarse sand.
COMPETING SERIES: These are the Chiwawa, Polander and Vinegar series. Chiwawa soils are dry for 60 to 75 consecutive days. Polander soils have 0 to 15 percent rock fragments and lack pumice fragments. Vinegar soils lack the skeletal discontinuity at 40 to 80 inches.
GEOGRAPHIC SETTING: Thow soils are on mountain slopes at 1,200 to 5,300 feet on generally northerly aspects. Slopes range from 5 to 90 percent. Thow soils formed in volcanic ash, pumice, and loess overlying ablation glacial till. The climate is characterized by warm, dry summers and cool, moist winters. The average annual precipitation is 18 to 27 inches. The mean January temperature is about 23 degrees F, the mean July temperature is about 68 degrees F, and the mean annual temperature is about 39 to 45 degrees F. The frost-free season is about 85 to 120 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bisping, Dinkelman, Thowson, Tillicum, McCree, Palmich, and Safety soils. Bisping, Safety, Dinkelman, and Thowson soils are mesic. McCree soils are loamy-skeletal. Palmich soils are cindery. Tillicum soils are medial over loamy.
DRAINAGE AND PERMEABILITY: Well drained; slow to rapid runoff; moderate permeability in the surface and subsoil and very rapid in the substratum.
USE AND VEGETATION: Used for woodland, wildlife habitat, watershed, recreation, and pasture. Native vegetation is Douglas-fir and ponderosa pine with an understory of pinegrass, elk sedge, spirea, arrowleaf balsamroot, lupine, and oceanspray.
DISTRIBUTION AND EXTENT: East slopes of the Cascade Mountains near Glacier Peak in Chelan and Okanogan Counties, Washington; MLRA 6. Series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Chelan County, Washington, 1969.
REMARKS: Diagnostic horizons and features recognized in this pedon are an ochric epipedon from the mineral surface to 9 inches and a cambic horizon from 9 to 43 inches. Andic soil properties are present from 1 to 43 inches.