LOCATION TERROR WA

Established Series
Rev. PHR/TMR/MPR
06/2011

TERROR SERIES

The Terror series consists of very deep, moderately well drained soils formed in volcanic ash overlying glacial drift and colluvium. Terror soils are found on slopes of 0 to 25 percent on floodplains, terraces, and valley walls of glaciated mountain landscapes. The mean annual precipitation is about 2,000 millimeters and the mean annual air temperature is about 4 degrees C.

TAXONOMIC CLASS: Ashy over loamy, amorphic over isotic Andic Dystrocryepts

TYPICAL PEDON: Terror ashy sandy loam, located on a forested southeast facing valley wall with a slope of 3 percent and an elevation of 1,725 meters. When described on August 19, 2007 the soil was slightly moist throughout. (Colors are for moist soil unless otherwise noted)

Oe--0 to 5 cm; moderately decomposed plant material; common very fine to fine and many medium roots; abrupt wavy boundary.

Oa--5 to 8 cm; highly decomposed plant material; common very fine to fine and many medium roots; abrupt wavy boundary.

A1--8 to 17 cm; very dark brown (10YR 2/2) ashy sandy loam, dark grayish brown (10YR 4/2) dry; weak fine subangular blocky structure; soft, very friable, nonsticky, nonplastic; common very fine to medium roots; very strongly acid (pH 5.0); clear wavy boundary.

A2--17 to 28 cm; black (10YR 2/1) ashy fine sandy loam, dark gray (10YR 4/1) dry; moderate medium subangular blocky structure; slightly hard, friable, nonsticky, nonplastic; few very fine to medium roots; very strongly acid (pH 5.0); abrupt wavy boundary.

Bw1--28 to 36 cm; dark brown (10YR 3/3) ashy sandy loam, brown (10YR 5/3) dry; moderate medium subangular blocky structure; slightly hard, friable, nonsticky, slightly plastic; few very fine to fine roots; very strongly acid (pH 5.0); abrupt wavy boundary.

2Bw2--36 to 52 cm; very dark grayish brown (10YR 3/2) cobbly sandy loam, grayish brown (10YR 5/2) dry; moderate medium subangular blocky structure; slightly hard, friable, slightly sticky, slightly plastic; few very fine to fine roots; 10 percent gravel and 10 percent cobbles; very strongly acid (pH 5.0); abrupt wavy boundary.

2Cg1--52 to 60 cm; light olive brown (2.5Y 5/3) gravelly coarse sandy loam, pale yellow (2.5Y 7/3) dry; weak fine subangular blocky structure; soft, very friable, nonsticky, nonplastic; few very fine roots; 30 percent dark brown (7.5YR 3/3) masses of oxidized iron; 5 percent fine gravel, 20 percent medium to coarse gravel and 5 percent cobbles; very strongly acid (pH 5.0); clear wavy boundary.

2Cg2--60 to 80 cm; light yellowish brown (2.5Y 6/4) gravelly coarse sandy loam, pale yellow (2.5Y 8/4) dry; weak fine subangular blocky structure; soft, very friable, nonsticky, nonplastic; 15 percent brown (7.5YR 4/4) masses of oxidized iron; 5 percent fine gravel, 20 percent medium to coarse gravel and 5 percent cobbles; very strongly acid (pH 5.0); clear wavy boundary.

2Cg3--80 to 150 cm; light yellowish brown (2.5Y 6/4) very gravelly coarse sandy loam, pale yellow (2.5Y 8/4) dry; weak fine subangular blocky structure; soft, very friable, nonsticky, nonplastic; 15 percent brown (7.5YR 4/4) masses of oxidized iron; 10 percent fine gravel, 20 percent medium to coarse gravel and 5 percent cobbles; very strongly acid (pH 5.0).

TYPE LOCATION: Chelan County, Washington; approximately 12 km northwest of the town of Stehekin along the western shore of Rainbow Lake, North Cascades National Park Service Complex; 725 m west and 710 m north of the southeast corner of section 33, T. 34 N., R. 17 E. Willamette Meridian; McAlester Mountain, Washington USGS quadrangle; 48 degrees, 24 minutes, 10 seconds north latitude and 120 degrees, 44 minutes, 31 seconds west longitude; UTM 667126 meters E, 5363556 meters N, zone 10N.

RANGE IN CHARACTERISTICS:
Mean annual soil temperature - 3 to 8 degrees C.
Moisture control section - dry less than 30 consecutive days.
Particle size control section:
The particle-size control section in this soil is contrasting. Most characteristics are listed by horizon
Clay content - 0 to 10 percent throughout both portions
Rock fragments, ashy portion - 0 to 30 percent total, 0 to 30 percent gravel, 0 to 15 percent cobbles
Rock fragments, loamy portion - 0 to 35 percent total, 0 to 30 percent gravel, 0 to 15 percent cobbles, 0 to 5 percent stones
Thickness of volcanic ash mantle (ashy textural modifier): 18 to 35 centimeters

A1 horizon
Hue - 10YR or 7.5YR
Value - 2 to 4 moist, 4 to 6 dry
Chroma - 1 to 2 moist or dry
Fine earth texture - ashy SL, ashy FSL, or ashy L
Rock fragments - 0 to 30 percent total, 0 to 30 percent fine to coarse gravel, 0 to 15 percent cobbles
Volcanic glass - 35 to 80 percent
Reaction - very strongly acid to strongly acid
Thickness - 5 to 20 centimeters

A2 horizon
Hue - 10YR or 7.5YR
Value - 2 to 4 moist, 4 to 6 dry
Chroma - 1 to 2 moist or dry
Fine earth texture - ashy FSL or ashy SL
Rock fragments - 0 to 30 percent total, 0 to 30 percent fine to coarse gravel, 0 to 15 percent cobbles
Volcanic glass - 35 to 80 percent
Reaction - very strongly acid to strongly acid
Thickness - 0 to 15 centimeters (may not be present in all pedons)

Bw1 horizon
Hue - 10YR, 7.5YR or 2.5Y
Value - 2.5 to 5 moist, 4 to 7 dry
Chroma - 1 to 4 moist or dry
Fine earth texture - ashy SL, ashy L, or ashy FSL
Rock fragments - 0 to 30 percent total, 0 to 30 percent fine to coarse gravel, 0 to 10 percent cobbles
Volcanic glass - 35 to 80 percent
Reaction - very strongly acid to strongly acid
Thickness - 10 to 30 centimeters

2Bw2 horizon
Hue - 10YR, 7.5YR or 2.5Y
Value - 3 to 5 moist, 5 to 7 dry
Chroma - 2 to 6 moist or dry
Fine earth texture - SL, COSL, or LS
Rock fragments - 5 to 30 percent total, 0 to 30 percent gravel, 0 to 15 percent cobbles, 0 to 5 percent stones
Reaction - very strongly acid to strongly acid
Combined thickness - 0 to 25 centimeters

2Cg horizons
Hue - 2.5Y or 10YR
Value - 3 to 6 moist, 5 to 8 dry
Chroma - 2 to 6 moist or dry
Fine earth texture - COSL, SL, LS or LCOS
Rock fragments - 5 to 35 percent total, 5 to 30 percent fine to coarse gravel, 0 to 15 percent cobbles, 0 to 5 percent stones
Reaction - very strongly acid to moderately acid
Combined Thickness - 15 to 100 centimeters

COMPETING SERIES: There are no competing series in this family.

GEOGRAPHIC SETTING: Terror soils are found on slopes of 0 to 25 percent on debris aprons, debris cones, and valley walls of glaciated mountain landscapes at elevations from 700 to 2,000 meters. They formed in volcanic ash overlying glacial drift and colluvium from glacial drift. The climate is characterized by cool, dry summers and cold, wet winters. Mean annual precipitation ranges from 1,400 to 2,500 millimeters. Mean annual air temperature ranges from 2 to 7 degrees C. Frost-free season is 30 to 60 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Chilliwack, Forbidden, and Yawning soils. Chilliwack soils have a medial fine earth fraction in the upper particle-size control section and have albic and spodic horizons. Forbidden soils have a sandy-skeletal particle size control section. Yawning soils have a loamy-skeletal particle size control section and albic and spodic horizons.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Moderately well drained; high to very high saturated hydraulic conductivity. Terror soils have a water table from endosaturation with an upper limit at 50 cm from the soil surface from November through May and ranging to below 150 cm from June through October.

USE AND VEGETATION: Terror soils are used for wildlife habitat, recreation, and watershed. Native vegetation includes subalpine fir, subalpine larch, Engelmann spruce, mountain hemlock, and occasionally at lower elevations Pacific silver fir and western hemlock. Understory species include western meadowrue, false hellebore, black huckleberry, prickly currant, Sitka alder, ladyfern and pink mountain heather.

DISTRIBUTION AND EXTENT: North Cascade Mountains, Washington. MLRA 3. Series is of small extent.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon

SERIES ESTABLISHED: North Cascades National Park Service Complex, Chelan County, Washington, 2011.

REMARKS: Diagnostic horizons and features recognized in this pedon include:
Cryic soil temperature regime.
Udic soil moisture regime.
Particle-size control section - 33 to 108 cm (25 to 100 cm from the mineral surface)
Ochric epipedon
Andic soil properties - the zone from 8 to 36 cm (A and Bw1 horizons)
Cambic horizon - 28 to 52 cm (Bw horizons)
Redox Concentrations - 52 to 150 cm (Cg horizons)

National Cooperative Soil Survey
U.S.A.