The Schwana plate. Relief from Copernicus GLO-30; rivers and lakes from USGS NHD; watersheds from the USGS Watershed Boundary Dataset; roads and city limits from Census TIGER 2024.
76° on Nov. 12, 1999, the hottest reading for this week of the year since 1956. Next is 69° in 1976.
Schwana’s center stands about 530 ft above sea level. Within three miles the land runs from 490 ft to 2,290 ft, a difference of 1,800 ft: steep hill country. The highest named summit within 15 miles is Hog Ranch Buttes, about 4,170 ft, 14 miles southwest.
The section below crosses 4 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 9×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Basalt. Age: Late Oligocene to Early Pliocene, 3.6 to 28 million years old. About 17 mi of the line.
Sandstone, clay, volcanic. Age: Pleistocene, less than 2.6 million years old. About 3 mi of the line.
Fine-detrital, coarse-detrital. Age: Pleistocene, less than 2.6 million years old. About 0.9 mi of the line.
Sand. Age: Holocene, less than 12,000 years old. About 0.6 mi of the line.
From the USGS State Geologic Map Compilation (Horton and others, 2017), the states’ geologic maps joined at a common scale.
Heights from Copernicus GLO-90 (a surface model: it includes buildings and tree canopy); summits from USGS GNIS; rivers from USGS NHDPlus HR; rock from the USGS State Geologic Map Compilation.
A raindrop that lands in Schwana reaches the Pacific Ocean by way of the Columbia: about 410 river miles.
Lake on the way: Lake Umatilla.
210 miles of the trip are on the Columbia.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Schwana; river miles along the main stem, rounded.
Schwana has a cold semi-arid climate. Summer afternoons average 92° in July; winter nights fall to about 30° in January. About 8 inches of rain fall in a normal year.
On November 14 Schwana normally reaches 50° and falls to 36°. The record high is 69°, in 2001; the record low 16°, in 2000. The most rain on this date, 0.59 in, fell in 1981.
Normals 1991–2020 and records since 1956 at Priest Rapids Dam, 12 miles south, 100 ft lower. NOAA, through RCC-ACIS.