LOCATION SENTINELPEAK WA
Tentative Series
IRD. MGR/AJF/MPR
01/2025
SENTINELPEAK SERIES
Landscape--mountains
Landform--colluvial aprons and glacial valley walls
Slope--35 to 100 percent
Parent material--colluvium from metasedimentary rock
Mean annual precipitation--about 1200 mm
Mean annual air temperature--about 10 degrees C
Depth class--very deep
Drainage class--well drained
Soil moisture regime--udic
Soil temperature regime--mesic
Soil moisture subclass--typic
TAXONOMIC CLASS: Loamy-skeletal, isotic, mesic Typic Dystrudepts
TYPICAL PEDON: Sentinelpeak gravelly loam on a south-facing, forested, glacial valley wall with a slope of 65 percent and an elevation of 400 m. (The soil was moist throughout when described.)
Oi--0 to 4 cm; slightly decomposed plant material; abrupt wavy boundary
Oe--4 to 8 cm; moderately decomposed plant material; abrupt wavy boundary
A--8 to 16 cm; brown (10YR 4/3) dry, dark brown (10YR 3/3) gravelly loam; weak fine granular structure; soft, very friable, slightly sticky, slightly plastic; many very fine and common fine roots; many fine irregular pores; 20 percent gravel; very strongly acid (pH 4.6); clear wavy boundary
Bw1--16 to 42 cm; brown (7.5YR 4/4) dry, dark brown (7.5YR 3/4) very gravelly loam; weak very fine subangular blocky structure; soft, very friable, slightly sticky, slightly plastic; common very fine, fine, and medium and few coarse and very coarse roots; many very fine irregular pores; 40 percent gravel; very strongly acid (pH 4.7); clear smooth boundary
Bw2--42 to 62 cm; brown (7.5YR 5/3) dry, brown (7.5YR 4/3) very gravelly loam; weak fine subangular blocky structure; soft, very friable, slightly sticky, slightly plastic; few fine and medium and common very fine roots; many very fine irregular pores; 40 percent gravel; very strongly acid (pH 4.8); gradual smooth boundary
Bw3--62 to 150 cm; brown (7.5YR 5/3) dry, brown (7.5YR 4/3) very gravelly loam; weak fine subangular blocky structure; soft, very friable, slightly sticky, slightly plastic; few very fine roots; common very fine irregular and few very fine interstitial pores; 55 percent gravel; very strongly acid (pH 4.8); clear smooth boundary
TYPE LOCATION: Clallam County, Washington, on Pyramid Peak Trail in Olympic National Park.
Latitude-- 48.0706560
Longitude-- -123.8372850
Datum--WGS84
RANGE IN CHARACTERISTICS:
Mean annual soil temperature--8 to 13 degrees C
Particle-size control section
*Clay content--8 to 17 percent
*Total rock fragment content--35 to 65 percent
*Gravel content--15 to 55 percent
*Cobble content--0 to 40 percent
*Stone content--0 to 20 percent
O horizon
Thickness--0 to 10 cm
A horizon
Hue--10YR or 7.5YR
Value--2 or 3 moist, 3 or 4 dry
Chroma--2 or 3, moist or dry
Fine-earth texture--silt loam, loam, or sandy loam
Clay content--8 to 15 percent
Total rock fragment content--10 to 40 percent
Gravel content--10 to 35 percent
Cobble content--0 to 15 percent
Reaction--4.5 to 5.5
Thickness--6 to 20 cm
Bw1 horizon
Hue--10YR or 7.5YR
Value--3 to 5 moist, 4 or 5 dry
Chroma--3 or 4, moist or dry
Fine-earth texture--silt loam, loam, or sandy loam
Clay content--8 to 17 percent
Total rock fragment content--35 to 60 percent
Gravel content--15 to 55 percent
Cobble content--0 to 40 percent
Stone content--0 to 20 percent
Reaction--4.5 to 5.5
Thickness--20 to 40 cm
Bw2 and Bw3 horizons
Hue--10YR or 7.5YR
Value--4 to 5 moist, 5 to 6 dry
Chroma--3 or 4, moist or dry
Fine-earth texture--silt loam, loam, or sandy loam
Clay content--8 to 17 percent
Total rock fragment content--35 to 60 percent
Gravel content--25 to 60 percent
Cobble content--0 to 40 percent
Stone content--0 to 20 percent
Reaction--4.5 to 5.5
Combined thickness--more than 100 cm
COMPETING SERIES:
Chamate--pH is 5.5 to 7.3 throughout
Piperock--lithic contact within 50 to 100 cm of the mineral soil surface
Remote--paralithic contact within 50 to 100 cm of the mineral soil surface
GEOGRAPHIC SETTING:
Elevation--300 to 1000 m
Climate--warm, dry summers; mild, wet winters
Mean annual precipitation--1000 to 1400 mm
Mean annual air temperature--8 to 12 degrees C
Frost-free period--180 to 240 days
GEOGRAPHICALLY ASSOCIATED SOILS:
Butlercreek--aquic conditions within 25 to 50 cm of the mineral soil surface; depressions on similar landforms
Dodgerpoint--lithic contact within 25 to 50 cm; 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--western hemlock, Douglas-fir, oceanspray, dwarf rose, western swordfern, sweet after death
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 Sentinel peak in Olympic National Park
REMARKS:
Diagnostic horizons and other features in this pedon:
*Particle-size control section--zone from 33 to 108 cm
*Ochric epipedon
*Cambic horizon--zone from 16 to 150 cm
National Cooperative Soil Survey
U.S.A.