The John Day 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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79° on Nov. 15, 1999, the hottest reading for this week of the year since 1903. Next is 73° in 2016.
John Day’s center stands about 3,080 ft above sea level. Within three miles the land runs from 2,990 ft to 4,120 ft, a difference of 1,130 ft: steep hill country. The highest named summit within 15 miles is Strawberry Mountain, about 8,990 ft, 14 miles east-southeast.
Under the town center the state geologic map shows Alluvial deposits (sand, gravel, silt), from the Holocene, less than 12,000 years old.
The section below crosses 10 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 4×. 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: Early Miocene to Middle Miocene, 12 to 23 million years old. About 6 mi of the line.
Peridotite, pyroxenite, gabbro. Age: Permian to Triassic, 202 to 299 million years old. About 4 mi of the line.
Coarse-detrital. Age: Pleistocene to Holocene, less than 2.6 million years old. About 4 mi of the line.
Gabbro. Age: Permian to Triassic, 202 to 299 million years old. About 3 mi of the line.
Sandstone, siltstone, mudstone. Age: Miocene to Pliocene, 2.6 to 23 million years old. About 2 mi of the line.
Sand, gravel, silt. Age: Holocene, less than 12,000 years old. About 1 mi of the line.
From the USGS State Geologic Map Compilation (Horton and others, 2017), the states’ geologic maps joined at a common scale. 4 smaller units 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 John Day reaches the Pacific Ocean by way of Canyon Creek, the John Day and the Columbia: about 460 river miles.
Lake on the way: Lake Umatilla.
240 miles of the trip are on the John Day.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of John Day; river miles along the main stem, rounded.
John Day has a warm-summer humid continental climate. Summer afternoons average 86° in July; winter nights fall to about 21° in January. A normal year brings about 10 inches of snow; with the rain, that comes to about 12 inches of water.
On November 14 John Day normally reaches 48° and falls to 26°. The record high is 75°, in 1999; the record low −7°, in 1955. The most rain on this date, 0.55 in, fell in 2006.
Normals 1991–2020 and records since 1903 at John Day, here. NOAA, through RCC-ACIS.
