LOCATION ALKIRIDGE WAEstablished Series
TAXONOMIC CLASS: Ashy over loamy-skeletal, glassy over isotic Typic Vitricryands
TYPICAL PEDON: Alkiridge sandy loam - clearcut area in a
small cirque basin, on a 25 percent west-facing
convex slope at 3,200 feet elevation. (Colors are for moist
soil unless otherwise stated. All textures are
for moist soil unless otherwise stated).
O--1 inch to 0; loose forest litter, needles, moss,
decayed bark and old roots. (1 to 2 inches thick)
A1--0 to 1 inch; very dark gray (10YR 3/1) loamy sand,
(volcanic ash), dark gray (10YR 4/1) dry; single
grain, loose, nonsticky and nonplastic; weakly smeary; many
very fine and fine, common medium and coarse roots;
5 percent hard subangular pebbles and 10 percent hard
cinders; strongly acid (pH 5.4); abrupt wavy boundary.
(1 to 2 inches thick)
A2--1 to 7 inches; dark brown (10YR 3/3) sandy loam,
(volcanic ash), brown (10YR 5/3) dry; weak fine
subangular blocky structure; soft, very friable, slightly
sticky and slightly plastic; weakly smeary; many very
fine, common fine, few coarse and medium roots; 10 percent
hard subangular pebbles and 10 percent hard cinder;
moderately acid (pH 5.6); abrupt smooth boundary. (0 to 6
inches thick)
Bhs--7 to 18 inches; dark brown (7.5YR 3/4) gravelly
sandy loam (volcanic ash), strong brown (7.5YR 5/6)
dry; weak fine subangular blocky structure; soft, very
friable, slightly sticky and slightly plastic; weakly
smeary; many very fine and few fine roots; 20 percent hard
subangular pebbles and 5 percent hard cinders;
medium acid (pH 5.8); clear wavy boundary. (8 to 13 inches
thick)
2BC1--18 to 28 inches; dark yellowish brown (10YR 4/4)
very gravelly loam, very pale brown (10YR 7/4) dry;
moderate fine and medium subangular blocky structure;
slightly hard, friable, slightly sticky and slightly
plastic; weakly smeary; many very fine and few fine roots;
30 percent subangular pebbles, 5 percent cobbles;
slightly acid (pH 6.4); clear wavy boundary. (7 to 10
inches thick)
2BC2--28 to 37 inches; olive brown (2.5Y 4/4) very
gravelly loam, pale yellow (2.5Y 7/4) dry; moderate fine
and medium subangular blocky structure; soft, friable,
slightly sticky and slightly plastic; weakly smeary; few
very fine and fine roots; 40 percent subangular pebbles, 10
percent cobbles; slightly acid (pH 6.2); clear
smooth boundary. (10 to 14 inches thick)
2Cr--37 inches; brown (10YR 4/3) dense glacial till,
that breaks to very gravelly sandy loam, pale brown
(10YR 6/3) dry; massive; hard, firm, slightly sticky,
slightly plastic; weakly smeary; 40 percent hard
subangular pebbles, 10 percent cobbles, and 5 percent
stones; slightly acid (pH 6.2).
TYPE LOCATION: Snoqualmie Pass Area, Pierce County,
Washington; along Forest Service Road #1819B, 900 feet
south and 2,600 feet east of the northwest corner sec. 14,
T. 18 N., R. 8 E.
RANGE IN CHARACTERISTICS: Depth to the paralithic contact
is 20 to 40 inches. Mean annual soil temperature
range from 41 to 46 degrees F. The spodic horizon is 8 to
11 inches and the particle-size control section
averages 35 to 60 percent rock fragments, and 5 to 10
percent hard cinders. Thickness of the ashy mantle is 14
to 20 inches.
The A horizon has a value of 2 or 3 moist, 3 through 5 dry,
and chroma of 1 through 3 moist or dry. It is
comprised of more than 60 percent coarse volcanic ash.
Reaction is strongly acid or moderately acid.
The Bhs horizon has hue of 10YR or 7.5YR, value of 3 or 4
moist, 5 or 6 dry, chroma of 3 through 6 moist or
dry. Texture is gravelly sandy loam or very gravelly sandy
loam, comprised of coarse volcanic ash and 20 to 30
percent pebbles, 0 to 5 percent cobbles, and 0 to 10 percent
hard cinders. Reaction is strongly acid or
moderately acid.
The 2BC horizon has hue of 10YR or 2.5Y, value of 4 or 5
moist, 6 or 7 dry, and chroma of 4 through 6 moist or
dry. It is 30 to 40 percent pebbles and 5 to 10 percent
cobbles. Reaction is moderately acid or slightly
acid.
The 2Cr horizon has hue of 10YR or 2.5Y, value of 4 or 5
moist, 5 or 6 dry, and chroma of 3 or 4 moist or dry.
When crushed, it is very gravelly loam or very gravelly
sandy loam with 30 to 40 percent pebbles, 10 to 15
percent cobbles and 5 to 10 percent stones.
COMPETING SERIES: These are the
Vanson soils and the
similar
Crinker,
Esmeralda,
Gilpar,
Hatchet, Howson,
Jackman,
Kachess,
Kindy,
Klawatti,
Lemah,
Ohana,
Playco,
Polallie,
Springsteen,
Thetis,
Vabus, and Waptus
series. Vanson soils are deep. The Crinker, Hatchet,
Howson, Klawatti, Polallie, and Springsteen soils are 20
to 40 inches deep to a lithic contact. Esmeralda, Gilpar,
Jackman, Kachess, Lemah, Playco, and Thetis soils
are more than 40 inches deep. Kindy soils lack the ashy
surface mantle and are silt loam or loam in the spodic
horizon. Ohana soils have 35 to 45 percent cinders in the
upper part of the spodic horizon and have a
paralithic contact with weathered tuff breccia. Vabus and
Waptus soils have a spodic horizon less than 7
inches thick and are sandy loam in the fine earth fraction
below the spodic horizon.
GEOGRAPHIC SETTING: Alkiridge soils are in cirque basins
and adjacent valley bottoms at elevations of 2,700 to
3,700 feet. Slope ranges from 8 to 30 percent. Alkiridge
soils formed in coarse volcanic ash and pumice over
colluvium, and glacial till overlying dense alpine glacial
till. Mean January temperature is 27 degrees F, the
mean July temperature is 60 degrees F, mean annual
temperature is 42 degrees F. Average annual precipitation
is 70 to 90 inches, with the majority of it in the form of
snow. The frost-free season is 110 to 130 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Haywire,
Littlejohn,
Nagrom,
Nimue, and
Pitcher series, and the
competing
Playco soils. Haywire and Nagrom soils have a
lithic contact at a depth of 20 to 40 inches.
Littlejohn and Pitcher soils are frigid. Nimue and Playco
soils are greater than 40 inches deep.
DRAINAGE AND PERMEABILITY: Moderately well drained; medium
runoff, moderate permeability to the dense glacial
till and very slow through it. A perched water table is as
high as 1.5 to 3 feet at times from November
through May.
USE AND VEGETATION: Used for timber production, wildlife
habitat, and watershed. Vegetation is western
hemlock, Pacific silver fir, Noble fir, Douglas-fir, and
western redcedar, with an undergrowth of common
beargrass, deer fern, Oregon-grape, salal, black mountain huckleberry, western swordfern, bunchberry dogwood,
and Pacific trillium.
DISTRIBUTION AND EXTENT: Western slopes of the Cascade
Mountains in westcentral Washington. Series is of
small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Snoqualmie Pass Area, Pierce County,
Washington, 1986.
REMARKS: Diagnostic horizons and features recognized in
this pedon are an ochric epipedon from the mineral
surface to 7 inches and a spodic horizon from 7 to 18 inches
both formed in volcanic ash, a subsoil from 18 to
37 inches that averages 42 percent rock fragments, and a
paralithic contact with dense glacial till at 38
inches.