LOCATION GRANDPASS WA
Tentative Series
IRD. MGR/AJF/MPR
01/2025
GRANDPASS SERIES
Landscape--mountains
Landform--glacial valley walls
Slope--15 to 100 percent
Parent material--colluvium from metasedimentary rock
Mean annual precipitation--about 2000 mm
Mean annual air temperature--about 2 degrees C
Depth class--very deep
Drainage class--well drained
Soil moisture regime--udic
Soil temperature regime--cryic
Soil moisture subclass--typic
TAXONOMIC CLASS: Loamy-skeletal, isotic Typic Dystrocryepts
TYPICAL PEDON: Grandpass loam on a southeast facing, forested glacial valley wall with a slope of 40 percent and an elevation of 1500 m. (The soil was moist throughout when described.)
Oi--0 to 2 cm; slightly decomposed plant material; abrupt smooth boundary
A1--2 to 12 cm; brown (7.5YR 4/2) dry, dark brown (7.5YR 3/2) loam; moderate medium granular structure; soft, very friable, slightly sticky slightly plastic; few fine, medium, and coarse and common very fine roots; few fine irregular and tubular pores; 5 percent gravel; very strongly acid (pH 4.6); clear smooth boundary
A2--12 to 19 cm; brown (7.5YR 4/3) dry, dark brown (7.5YR 3/2) loam; weak fine granular structure; soft, very friable, slightly sticky, slightly plastic; few very fine, fine, and very coarse, and common medium roots; few very fine irregular and few fine tubular pores; 5 percent gravel, 5 percent cobbles; very strongly acid (pH 4.6); abrupt smooth boundary
Bw1--19 to 38 cm; brown (7.5YR 5/3) dry, dark brown (7.5YR 3/3) gravelly loam; weak very fine subangular blocky structure; soft, very friable, moderately sticky, moderately plastic; few medium and coarse and common fine roots; few fine irregular and interstitial pores; 15 percent gravel, 5 percent cobbles; very strongly acid (pH 4.7); abrupt wavy boundary
Bw2--38 to 75 cm; brown (7.5YR 5/4) dry, dark brown (7.5YR 3/4) very gravelly loam; weak very fine subangular blocky structure; soft, very friable, slightly sticky, moderately plastic; few fine and medium roots; common fine interstitial pores; 45 percent gravel, 10 percent cobbles; very strongly acid (pH 4.8); clear smooth boundary
Bw3--75 to 150 cm; brown (7.5YR 5/4) dry, dark brown (7.5YR 3/4) extremely gravelly loam; weak very fine subangular blocky structure; soft, very friable, slightly sticky, moderately plastic; few fine and medium roots; common fine interstitial pores; 55 percent gravel, 10 percent cobbles; very strongly acid (pH 4.8); clear smooth boundary
TYPE LOCATION: Clallam County, Washington
Latitude--48.0063980
Longitude-- -123.6623950
Datum--WGS84
RANGE IN CHARACTERISTICS:
Mean annual soil temperature--0 to 3 degrees C
Particle-size control section
*Clay content--8 to 18 percent
*Total rock fragment content--40 to 70 percent
*Gravel content--35 to 60 percent
*Cobble content--0 to 20 percent
*Stone content--0 to 15 percent
Oi horizon
Thickness--0 to 5 cm
A1 and A2 horizons
Hue--10YR or 7.5YR
Value--2 to 4 dry or moist
Chroma--2 to 3 dry or moist
Fine-earth texture--silt loam, loam, sandy loam
Clay content--8 to 18 percent
Total rock fragment content--0 to 30 percent
Gravel content--0 to 25 percent
Cobble content--0 to 15 percent
Reaction--4.5 to 5.5
Combined thickness--15 to 30 cm
Bw1 horizon
Hue--10YR or 7.5YR
Value--3 to 5 dry or moist
Chroma--3 to 4 dry or moist
Fine-earth texture--silt loam, loam, sandy loam
Clay content--8 to 18 percent
Total rock fragment content--10 to 40 percent
Gravel content--5 to 35 percent
Cobble content--0 to 15 percent
Reaction--4.5 to 5.5
Thickness--15 to 25 cm
Bw2 and Bw3 horizons
Hue--10YR or 7.5YR
Value--3 to 5 dry or moist
Chroma--3 or 4 dry or moist
Fine-earth texture--silt loam, loam, sandy loam
Clay content--8 to 18 percent
Total rock fragment content--40 to 70 percent
Gravel content--35 to 60 percent
Cobble content--0 to 20 percent
Stone content--0 to 15 percent
Reaction--4.5 to 5.5
Combined thickness--more than 100 cm
COMPETING SERIES:
Bensley--particle size control section contains 18 to 30 percent clay
Cascadecreek--has a C horizon with structureless, single grain structure
Fallriver--contains an albic horizon, particle size control section contains 15 to 30 percent mica
Henson--particle size control section contains 18 to 35 percent clay
Stuyahok--has a C horizon that is very firm and hard with a pH range of 5.6 to 6.0
Golsovia--paralithic contact within 100 to 150 cm of the soil surface
Kanguq--paralithic contact within 50 to 100 cm of the soil surface
Sharp--lithic contact within 100 to 150 cm of the soil surface
Mountstone --mean annual soil temperature is 4 to 7 degrees C
Endlich and Marmotlake--lithic contact within 50 to 100 cm of the soil surface
GEOGRAPHIC SETTING:
Elevation--1400 to 1900 m
Climate--cool, dry summers; cold, wet winters
Mean annual precipitation--1750 to 2500 mm
Mean annual air temperature--0 to 4 degrees C
Frost-free period--30 to 60 days
GEOGRAPHICALLY ASSOCIATED SOILS:
Mountfromme--lithic contact within 25 to 50 cm of the soil surface; similar landforms
Lollah--umbric epipedon; similar landforms
Marmotpass--lithic contact within 50 to 100 cm of the soil surface; similar landforms
Ringlake--aquic conditions within 0 to 25 cm of the mineral soil surface; depressions on similar landforms
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class--well drained
Saturation in normal years--none
Flooding--none
Ponding--none
Saturated hydraulic conductivity (Ksat)--high or very high throughout
USE AND VEGETATION:
Use--wildlife habitat, recreation
Potential natural vegetation--Subalpine fir, lodgepole pine, common juniper, Oregon boxleaf, broadleaf lupine, desertparsley
DISTRIBUTION AND EXTENT: Olympic Mountains, Washington; MLRA 1; moderate extent
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Bozeman, Montana
SERIES PROPOSED: Olympic National Park, Clallam County, Washington 2023; name from Grand pass in Olympic National Park
REMARKS:
Diagnostic horizons and other features in this pedon:
*Particle-size control section--zone from 27 to 102 cm
*Ochric epipedon
*Cambic horizon--19 to 150 cm
National Cooperative Soil Survey
U.S.A.