The Pioneer Junction 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.
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69° on Nov. 13, 1999, the hottest reading for this week of the year since 1986. Next is 61° in 1995.
Pioneer Junction’s center stands about 2,280 ft above sea level. Within three miles the land runs from 2,130 ft to 4,130 ft, a difference of 2,000 ft: steep hill country. The highest named summit within 15 miles is Snowshoe Peak, about 8,550 ft, 11 miles southwest.
Under the town center the state geologic map shows Alluvium (gravel, sand, silt), from the Pleistocene to Holocene, less than 1.8 million years old.
The section below crosses 7 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 3×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Metasiltstone, argillite. Age: Mesoproterozoic, 1 to 1.6 billion years old. About 7 mi of the line.
Quartzite, metasiltstone, argillite. Age: Mesoproterozoic, 1 to 1.6 billion years old. About 6 mi of the line.
Unconsolidated. Age: Pleistocene to Holocene, less than 1.8 million years old. About 5 mi of the line.
Gravel, sand, silt. Age: Pleistocene to Holocene, less than 1.8 million years old. About 2 mi of the line.
Quartzite, argillite, metasiltstone. Age: Mesoproterozoic, 1 to 1.6 billion years old. About 2 mi of the line.
Metasiltstone, argillite, quartzite. Age: Mesoproterozoic, 1 to 1.6 billion years old. About 0.9 mi of the line.
From the USGS State Geologic Map Compilation (Horton and others, 2017), the states’ geologic maps joined at a common scale. 1 smaller unit along the line are not listed.
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 Pioneer Junction reaches the Pacific Ocean by way of Libby Creek, the Kootenai and the Columbia: about 830 river miles.
Lake on the way: Lake Umatilla.
460 miles of the trip are on the Columbia.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Pioneer Junction; river miles along the main stem, rounded.
Pioneer Junction has a warm-summer humid continental climate. Summer afternoons average 85° in July; winter nights fall to about 21° in February. About 17 inches of rain fall in a normal year.
On November 14 Pioneer Junction normally reaches 43° and falls to 28°. The record high is 56°, in 1999; the record low 8°, in 2014. The most rain on this date, 0.60 in, fell in 2006.
Normals 1991–2020 and records since 1986 at Libby Dam (Base), 11 miles east-northeast, 170 ft lower. NOAA, through RCC-ACIS.
