LOCATION OHANAPECOSH WA
Established Series
IRD. TMR/MPR
07/2017
OHANAPECOSH SERIES
Landscape--Cascade Mountains
Landform--debris aprons, bedrock benches, ridges, glacial valley walls
Slope--5 to 100 percent
Parent material--volcanic ash over andesite
Mean annual precipitation--about 2000 mm
Mean annual air temperature--about 5 degrees C
Depth class--shallow
Drainage class--well drained
Soil moisture regime--udic
Soil temperature regime--cryic
Soil moisture subclass--typic
TAXONOMIC CLASS: Ashy, amorphic Lithic Haplocryods
TYPICAL PEDON: Ohanapecosh ashy loamy sand on a forested, west-facing debris apron with a slope of 35 percent and at an elevation of 750 m (When described on September 29, 2011, the soil was slightly moist throughout.)
Oi--0 to 1 cm; slightly decomposed plant material from deciduous shrubs, conifer needles, and twigs; many fine interstitial pores; very strongly acid (pH 4.5); abrupt smooth boundary
Oe--1 to 3 cm; moderately decomposed plant material; few very fine and fine roots; many fine interstitial pores; very strongly acid (pH 4.5); abrupt smooth boundary
E--3 to 14 cm; ashy loamy sand, gray (7.5YR 5/1) dry, dark gray (7.5YR 4/1) moist; weak fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine to medium roots; common very fine and fine interstitial pores; 5 percent pumice paragravel; strongly acid (pH 5.2); abrupt irregular boundary
Bs1--14 to 30 cm; paragravelly ashy sandy loam, brown (7.5YR 5/4) dry, dark brown (7.5YR 3/4) moist; moderate medium subangular blocky structure; slightly hard, friable, nonsticky and nonplastic; common very fine to coarse roots; many very fine and fine interstitial pores; 20 percent pumice paragravel; moderately acid (pH 5.7); clear irregular boundary
Bs2--30 to 45 cm; paragravelly ashy sandy loam, brown (7.5YR 5/3) dry, dark brown (7.5YR 3/3) moist; moderate coarse subangular blocky structure; slightly hard, friable, nonsticky and nonplastic; few very fine to medium roots; common very fine and fine interstitial pores; 20 percent pumice paragravel and 5 percent andesite cobbles; moderately acid (pH 5.7); abrupt irregular boundary
2R--45 cm; fractured andesite
TYPE LOCATION: Pierce County, Washington, upslope from Washington State Route 123, adjacent to Shriner Peak Trail, about 8 km northeast of the Ohanapecosh Ranger Station in Mount Rainier National Park; about 390 m north and 350 m west of the southeast corner of section 9, T. 15 N., R. 10 E., Willamette Meridian; Chinook Pass, Washington, U.S. Geological Survey quadrangle; latitude 46.801261 degrees north, longitude -121.554850 degrees west, datum WGS 84 (coordinates determined with a GPS)
RANGE IN CHARACTERISTICS:
Mean annual soil temperature--4 to 8 degrees C
Soil moisture control section--dry less than 45 consecutive days in June through October
Depth to lithic contact--25 to 50 cm
All mineral horizons
*Volcanic glass content--50 to 75 percent
*Ammonium oxalate Al plus 1/2 Fe--greater than 0.5 percent
*Clay content--1 to 10 percent
*Pararock and rock fragment content--5 to 30 percent total, with pumice paragravel typically in upper part of profile and andesite gravel or cobbles in lower part in some areas
*Organic carbon content--less than 6 percent
O horizon
*In lieu of texture--slightly decomposed plant material, moderately decomposed plant material
*Thickness--0 to 5 cm
E horizon
*Hue--7.5YR, 10YR
*Value--4 or 5 moist, 5 to 7 dry
*Chroma--1 or 2 moist or dry
*Fine-earth texture--ashy loamy sand, ashy sandy loam
*Clay content--1 to 10 percent
*Pararock fragment content--0 to 10 percent pumice paragravel
*Reaction--4.5 to 5.5
*Thickness--5 to 10 cm
Bs1 horizon
*Hue--7.5YR, 5YR, 10YR
*Value--2 to 4 moist, 4 or 5 dry
*Chroma--2 to 4 moist or dry
*Fine-earth texture--ashy sandy loam, ashy coarse sandy loam, ashy loamy sand
*Clay content--1 to 10 percent
*Pararock fragment content--5 to 30 percent pumice paragravel
*Reaction--5.1 to 6.0
*Thickness--10 to 20 cm
Bs2 horizon
*Hue--7.5YR, 10YR
*Value--2 to 4 moist, 4 or 5 dry
*Chroma--2 to 4 moist or dry
*Fine-earth texture--ashy sandy loam, ashy coarse sandy loam, ashy fine sandy loam
*Clay content--1 to 10 percent
*Pararock and rock fragment content--5 to 35 percent total, including 5 to 30 percent pumice paragravel, 0 to 10 percent gravel, and 0 to 10 percent cobbles
*Reaction--5.1 to 6.0
*Thickness--10 to 20 cm
COMPETING SERIES: None
GEOGRAPHIC SETTING:
Elevation--650 to 1500 m
Climate--cool, dry summers; cold, wet winters
Mean annual precipitation--1600 to 2700 mm
Mean annual air temperature--3 to 7 degrees C
Frost-free period--60 to 90 days
GEOGRAPHICALLY ASSOCIATED SOILS:
Arahustan--50 to 100 cm deep to lithic contact (moderately deep); in similar landform positions
Longmire--greater than 150 cm deep to lithic contact (very deep); in similar landform positions
Frogheaven--aquic conditions within 25 cm of the soil surface; in depressions and swales with prolonged periods of saturation
Vantrump--aquic conditions with an upper limit of 25 cm from the soil surface; on debris aprons and glacial valley walls on gentler slopes that receive upslope runoff
Laughingwater--aquic conditions with an upper limit of 50 cm from the soil surface; in similar landform positions on gentler slopes that receive upslope runoff
Summerland--umbric epipedon; no albic horizon; associated with deciduous forests in active avalanche paths
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage--well drained
Saturated hydraulic conductivity (Ksat)--high or very high throughout
USE AND VEGETATION:
Use--wildlife habitat, recreation
Potential natural vegetation--Pacific silver fir, noble fir, Douglas-fir, western hemlock, vine maple, Cascade Oregon grape, salal, rattlesnake plantain, twinflower, vanillaleaf, prince's pine, pachistima, beargrass
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 Ohanapecosh River in Mount Rainier National Park
REMARKS:
Diagnostic horizons and other features in this pedon
*Particle-size control section--zone from 3 to 45 cm
*Ochric epipedon
*Albic horizon--zone from 3 to 14 cm
*Spodic horizon--zone from 14 to 45 cm
*Andic soil properties--zone from 3 to 45 cm
*Depth to lithic contact--45 cm
*Distinguishable tephra layers--Mount St. Helens T and Wn tephra (E horizon), Mount Rainier C tephra (Bs1 horizon), Mount St. Helens Yn tephra (Bs2 horizon)
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.
National Cooperative Soil Survey
U.S.A.