LOCATION COMET                   WA

Established Series
Rev. SMB/PHR/MPR
07/2017

COMET SERIES

Landscape--river valleys
Landform--flood plains, terraces
Slope--0 to 10 percent
Parent material--alluvium derived from andesite mixed with volcanic ash
Mean annual precipitation--about 1800 mm
Mean annual air temperature--about 6 degrees C
Depth class--very deep
Drainage class--somewhat excessively drained
Soil moisture regime--udic
Soil temperature regime--frigid
Soil moisture subclass--typic

TAXONOMIC CLASS: Ashy-skeletal, glassy, frigid Vitrandic Humudepts

TYPICAL PEDON: Comet very gravelly ashy sandy loam on a forested terrace with a slope of 3 percent and at an elevation of 615 m (When described on August 6, 2012, the soil was moist throughout.)

Oi--0 to 2 cm; slightly decomposed plant material; very strongly acid (pH 4.5); clear wavy boundary

Oe--2 to 4 cm; moderately decomposed plant material; many very fine and fine and common medium to very coarse roots; very strongly acid (pH 4.5); clear wavy boundary

A1--4 to 28 cm; very gravelly ashy sandy loam, dark gray (10YR 4/1) dry, black (10YR 2/1) moist; weak fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine and medium, many fine, and few coarse and very coarse roots; common fine irregular pores; 10 percent fine gravel, 30 percent medium and coarse gravel, and 15 percent cobbles; strongly acid (pH 5.4); clear wavy boundary

A2--28 to 46 cm; very gravelly ashy loamy sand, dark gray (10YR 4/1) dry, black (10YR 2/1) moist; weak fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine and fine and few medium to very coarse roots; common fine interstitial pores; 10 percent fine gravel, 30 percent medium and coarse gravel, and 10 percent cobbles; strongly acid (pH 5.4); clear wavy boundary

A3--46 to 71 cm; very gravelly ashy loamy sand, dark gray (10YR 4/1) dry, black (10YR 2/1) moist; weak fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; few very fine to medium roots; common fine interstitial pores; 10 percent fine gravel, 15 percent medium and coarse gravel, and 10 percent cobbles; strongly acid (pH 5.4); clear wavy boundary

A4--71 to 93 cm; very gravelly ashy loamy sand, gray (10YR 5/1) dry, very dark gray (10YR 3/1) moist; weak fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine and fine and few medium to very coarse roots; common fine interstitial pores; 10 percent fine gravel, 20 percent medium and coarse gravel, and 10 percent cobbles; strongly acid (pH 5.4); clear wavy boundary

A5--93 to 105 cm; very gravelly ashy fine sandy loam, dark gray (10YR 4/1) dry, black (10YR 2/1) moist; weak fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; few very fine to very coarse roots; common fine interstitial pores; 1 percent dark reddish brown (5YR 3/4) masses of oxidized iron with diffuse boundaries along root channels; 10 percent fine gravel, 25 percent medium and coarse gravel, and 20 percent cobbles; moderately acid (pH 5.7); clear wavy boundary

C--105 to 150 cm; extremely cobbly ashy fine sandy loam, gray (10YR 6/1) dry, very dark gray (10YR 3/1) moist; weak fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; few very fine to very coarse roots; common fine interstitial pores; 1 percent dark reddish brown (5YR 3/4) masses of oxidized iron with diffuse boundaries along root channels; 10 percent fine gravel, 25 percent medium and coarse gravel, and 25 percent cobbles; moderately acid (pH 5.7)

TYPE LOCATION: Pierce County, Washington, about 200 m southeast of the Nisqually Entrance to Mount Rainier National Park, on a small terrace north of the Nisqually River; about 425 m north and 105 m east of the southwest corner of section 34, T. 15 N., R. 7 E., Willamette Meridian; Sawtooth Ridge, Washington, U.S. Geological Survey quadrangle; latitude 46.73963 degrees north, longitude -121.91666 degrees west, datum WGS 84 (coordinates determined with a GPS)

RANGE IN CHARACTERISTICS:
Mean annual soil temperature--6 to 8 degrees C
Soil moisture control section--dry less than 45 consecutive days in June through October
Depth to redoximorphic iron concentrations--60 to 150 cm below the mineral soil surface
Thickness of umbric epipedon--40 to 75 cm

All mineral horizons
*Volcanic glass content--50 to 75 percent glass and glass-coated minerals
*Ammonium oxalate Al plus 1/2 Fe--less than 0.4 percent
*Reaction--5.1 to 6.0

Particle-size control section
*Clay content--0 to 7 percent
*Rock fragment content--35 to 60 percent total, including 15 to 50 percent fine to coarse gravel, 5 to 25 percent cobbles, 0 to 20 percent stones, and 0 to 20 percent boulders

Oi and Oe horizons
*Combined thickness--2 to 7 cm

A1 horizon
*Value--2 or 3 moist, 3 to 5 dry
*Chroma--1 or 2 moist or dry
*Organic carbon content--greater than 0.6 percent
*Fine-earth texture--ashy sandy loam, ashy loamy sand
*Rock fragment content--35 to 60 percent total, including 5 to 15 percent fine gravel, 15 to 40 percent medium and coarse gravel, 0 to 20 percent cobbles, and 0 to 10 percent stones
*Thickness--15 to 30 cm

A2 horizon
*Hue--7.5YR, 10YR
*Value--2 or 3 moist, 3 to 5 dry
*Chroma--1 to 3 moist or dry
*Organic carbon content--greater than 0.6 percent
*Fine-earth texture--ashy loamy sand, ashy sand, ashy sandy loam
*Rock fragment content--35 to 60 percent total, including 5 to 20 percent fine gravel, 10 to 40 percent medium and coarse gravel, 0 to 20 percent cobbles, 0 to 15 percent stones, and 0 to 10 percent boulders
*Thickness--15 to 30 cm

A3 horizon
*Hue--7.5YR, 10YR, 2.5Y
*Value--2 or 3 moist, 3 to 5 dry
*Chroma--1 to 3 moist or dry
*Organic carbon content--greater than 0.6 percent
*Fine-earth texture--ashy loamy sand, ashy sand, ashy sandy loam
*Rock fragment content--15 to 50 percent total, including 5 to 25 percent fine gravel, 10 to 30 percent medium and coarse gravel, 0 to 25 percent cobbles, 0 to 15 percent stones, and 0 to 15 percent boulders
*Thickness--10 to 30 cm

A4 horizon
*Hue--7.5YR, 10YR, 2.5Y
*Value--2 or 3 moist, 3 to 6 dry
*Chroma--1 to 3 moist or dry
*Organic carbon content--less than 0.6 percent
*Fine-earth texture--ashy loamy sand, ashy sand, ashy sandy loam
*Rock fragment content--35 to 60 percent total, including 10 to 25 percent fine gravel, 10 to 30 percent medium and coarse gravel, 0 to 30 percent cobbles, 0 to 20 percent stones, and 0 to 20 percent boulders
*Thickness--20 to 35 cm

A5 horizon
*Hue--7.5YR, 10YR, 2.5Y
*Value--2 to 4 moist, 3 to 6 dry
*Chroma--1 to 3 moist or dry
*Organic carbon content--less than 0.6 percent
*Fine-earth texture--ashy fine sandy loam, ashy loamy sand, ashy sand
*Rock fragment content--35 to 60 percent total, including 10 to 25 percent fine gravel, 10 to 30 percent medium and coarse gravel, 5 to 30 percent cobbles, 0 to 20 percent stones, and 0 to 20 percent boulders
*Thickness--10 to 45 cm

C horizon
*Hue--7.5YR, 10YR, 2.5Y
*Value--2 to 4 moist, 3 to 6 dry
*Chroma--1 to 3 moist or dry
*Organic carbon content--less than 0.6 percent
*Fine-earth texture--ashy fine sandy loam, ashy sand, ashy loamy sand
*Rock fragment content--40 to 65 percent total, including 10 to 25 percent fine gravel, 10 to 30 percent medium and coarse gravel, 5 to 30 percent cobbles, 0 to 20 percent stones, and 0 to 20 percent boulders

COMPETING SERIES: None

GEOGRAPHIC SETTING:
Elevation--500 to 650 m
Climate--warm, dry summers; cool, wet winters
Mean annual precipitation--1,600 to 2,000 mm
Mean annual air temperature--5 to 7 degrees C
Frost-free season--90 to 130 days

GEOGRAPHICALLY ASSOCIATED SOILS:
Carbon--less than 35 percent rock fragments in particle-size control section; aquic conditions below a depth of 50 to 60 cm from the mineral soil surface; in similar landform positions
Sunbeam--aquic conditions within 25 cm of the mineral soil surface; in depressions of flood plains and terraces
Kautz, Tokaloo--andic soil properties throughout; formed in volcanic ash and colluvium; on nearby valley walls and debris aprons

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class--somewhat excessively drained
Saturated hydraulic conductivity (Ksat)--very high
Frequency of flooding--rare

USE AND VEGETATION:
Use--wildlife habitat, recreation
Potential natural vegetation--black cottonwood, western hemlock, western redcedar, Douglas-fir, grand fir, red alder, bigleaf maple, vine maple, western swordfern, Cascade Oregon grape, vanillaleaf, fireweed, red huckleberry, Oregon oxalis

DISTRIBUTION AND EXTENT: Central Cascade Mountains, Washington; MLRA 3; small extent

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

SERIES ESTABLISHED: Mount Rainier National Park, Pierce County, Washington, 2014; name from Comet Falls in Mount Rainier National Park

REMARKS:
Diagnostic horizons and others features in this pedon
*Particle-size control section--zone from 29 to 104 cm
*Umbric epipedon--zone from 4 to 71 cm
*Volcanic glass--zone from 4 to 150 cm
*Redoximorphic concentrations--zone from 93 to 150 cm

3/2017--This official series description was updated according to SSR1 Technical Note 11--Content and Format of Official Series Descriptions (revised 12/2015). Most of the changes were in formatting; no major technical changes were made.

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National Cooperative Soil Survey
U.S.A.