Physiographic features

Physiographic Features
Landscapes: Mountains, Foothills, Valleys
Landform: sideslopes, foot slopes, outwash terraces, escarpments

Elevation (m): Total range = 435 to 1340 m
(1,425 to 4,400 feet)
Central tendency = 725 to 1090 m
(2,380 to 3,575 feet)



Slope (percent): Total range = 0 to 45 percent
Central tendency = 6 to 28 percent

Water Table Depth (cm):
90 cm to >200 cm (median = >200cm)
(35 to >80 inches; median = >80 inches)

Flooding:
Frequency: None
Duration: None


Ponding:
Frequency: None
Duration: None


Aspect: (central tendency)
105-197-255

Table 2. Representative physiographic features

Table 3. Representative physiographic features (actual ranges)

Climatic features

Climatic Features

During the spring and summer, a circulation of air around a high-pressure center brings a prevailing westerly and northwesterly flow of comparatively dry, cool and stable air into the region. As the air moves inland, it becomes warmer and drier which results in a dry season beginning in the late spring and reaching a peak in mid-summer. In the fall and winter, a circulation of air around two pressure centers over the ocean brings a prevailing southwesterly and westerly flow of air into the Pacific Northwest. This air from over the ocean is moist and near the temperature of the water. Condensation occurs as the air moves inland over the cooler land and rises along the windward slopes of the mountains or highlands. This results in a wet season beginning in October, reaching a peak in winter, then gradually decreasing in the spring.

The elevation within the LRU varies from approximately 1,500 feet in the lower river valleys to over 7,000 feet in the higher terrain. The annual precipitation increases from 20 inches in the valleys to over 52 inches over the higher mountains. Winter season snowfall varies from 30 to 50 inches. Both rainfall and snowfall increase in the higher elevations. Snow can be expected after the first of November and to remain on the ground from the first of December until March or April.

In January, the average maximum temperature is near 31° F and the minimum temperature is 18° F. Minimum temperatures from -10° to -20°F are recorded almost every winter and temperatures ranging to -30° F have been recorded. In July, the average maximum temperature is 85° to 90° and the minimum temperature 45° to 50° F. Maximum temperatures reach 100° F on a few afternoons each summer and temperatures between 105° to 110° F have been recorded. Temperatures in the mountains decrease three to five degrees Fahrenheit with each 1,000 feet increase in elevation. The average date of the last freezing temperatures can be expected by mid-May and before mid-October in the warmer areas.
(Compiled from WRCC: Climate of Washington and available station data)

Climatic Features
Frost-free period (days): Total range = 90 to 130 days
Central tendency = 105 to 120 days

Mean annual precipitation (cm): Total range = 320 to 1165 mm
(13 to 46 inches)
Central tendency = 595 to 825 mm
(23 to 32 inches)


MAAT (C): Total range = 3.3 to 9.3
(38 to 49 F)
Central tendency = 6.0 to 7.8
(43 to 46 F)

Climate Stations: none

Table 4. Representative climatic features

Influencing water features

Soil features

Representative Soil Features

This ecological subsite is associated with several soil series (e.g. Merkel, Tamarack, Wilma, Chewelah, Clayton, Orwig, Quinnamose, Kruse). The soil components can be grouped into: Vitrandic Dystroxerepts, Lamellic Haploxeralfs, and Vitrandic Haploxerepts. These soils have developed in thin or mixed Mazama tephra deposits over till, glaciolacustrine, outwash and residuum and colluvium from granitic and metamorphic rock.. The soils range from moderately deep to very deep and have adequate available water capacity to a depth of 1 m. The soils are mostly well-drained.


Parent Materials:
Kind: Tephra (volcanic ash)
Origin: mixed
Kind: till, residuum and colluvium, and outwash material
Origin: Granite, Metamorphic rock

Surface Texture: (<2mm fraction)
(1) Ashy-Sandy Loam
(2) Ashy-Silt loam
(3) Ashy-Fine Sandy Loam

Fragment content of surface: 0 to 20 percent (median = 6%)

Subsurface Texture Group: Loamy
Fragment content of subsurface (25 to 100cm): 0 to 58 percent (median = 14%)
Most components lack surface fragments
Drainage Class: Well drained (6% Somewhat Poorly drained components)
Saturated Hydraulic conductivity: Moderately high to High (above restrictions)
Soil Depth: 79% of components have no restriction within 150 cm
Lithic contacts when present are at 48 to 110cm (median = 48cm)
Densic contacts when present are at 65 to 100cm (median = 99 cm)
Calcium Carbonate Equivalent (percent): 0 to 15 (median = 0)
Soil Reaction (1:1 Water): 5.6 to 8.0
Available Water Capacity (total in 100cm): 6.16-19.47cm (median = 11.75 cm)

Table 5. Representative soil features

Table 6. Representative soil features (actual values)

Approval

Curtis Talbot, 10/14/2020