63—Umak paragravelly ashy fine sandy loam, dry, 0 to 10 percent slopes

 Map Unit Setting

 General location: Pumice flows in valleys in the southeastern part of the park

Major land resource area (MLRA): 3

Elevation: 5,000 to 5,500 feet

Average annual precipitation: 40 to 60 inches

Average annual air temperature: 38 to 42 degrees F

Frost-free period: 0 to 50 days

 Map Unit Composition

 Umak and similar soils: 85 percent

Minor components: 15 percent

 Characteristics of the Umak and Similar Soils

 Setting

 Landform: Ashflow

Geomorphic position: Valleys

Parent material: Pumice and ash

 Properties and qualities

 Slope: 0 to 10 percent

Percentage of surface covered with stones and boulders: None

Restrictive features: None within a depth of 60 inches

Drainage class: Excessively drained

Permeability: Very rapid

Flooding: Not present

Water table: Not present

Ponding: Not present

Available water capacity: About 7.8 inches

 Interpretive groups

 Ecological site: Forestland—(003XY708OR) Abies-Pinus monticola/Arctostaphylos nevadensis

 Typical profile

 Oi—0 to 1 inch; slightly decomposed plant material

A—1 inch to 5 inches; paragravelly ashy fine sandy loam

Bw1—5 to 21 inches; very paracobbly ashy coarse sandy loam

Bw2—21 to 43 inches; extremely paracobbly ashy loamy coarse sand

Bw3—43 to 62 inches; extremely paracobbly ashy loamy coarse sand

 Characteristics of the Minor Components

 Timbercrater soils

Percentage of map unit: 10 percent

Landform: Ashflow

Geomorphic position: Ashfall and ashflow deposits with gravel-sized pumice in valleys

 Castlecrest soils

 Percentage of map unit: 5 percent

Landform: Ashflow

Geomorphic position: Ash deposits in valleys

 Major Soil Features and Properties Affecting Management

 Umak soil

 • High pumice content

• Paracobbles on surface and in profile

• Very rapid permeability

 

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