These are the Estrella and Trix series. Both soils have buried argillic horizons between 20 and 40 inches. Avondale soils are on nearly level flood plains and alluvial fans. Elevation ranges from 400 to 2500 feet. They formed in medium and moderately fine textured alluvium derived from mixed basic and acid igneous rocks, quartzite and limestone.
Avondale soils are in an arid or semiarid continental climate.
Average annual precipitation ranges from 3 to 10 inches and falls mainly during the summer and winter. The soil receives additional moisture during summer in runoff from adjacent soils. These are the Antho , Cashion , Gilman , Glenbar , Pimer and Vint soils. Antho and Gilman soils are coarse-loamy. Cashion soils are clayey over loamy.