The Declo 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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75° on Nov. 12, 1999, the hottest reading for this week of the year since 1917. Next is 71° in 1934.
Declo’s center stands about 4,210 ft above sea level. Within three miles the land runs from 4,130 ft to 4,510 ft, a difference of 380 ft: rolling country. The highest named summit within 15 miles is Mount Harrison, about 9,250 ft, 15 miles south.
The section below crosses 6 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 8×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Coarse-detrital, fine-detrital. Age: Pleistocene to Holocene, less than 33,000 years old. About 12 mi of the line.
Rhyolite. Age: Middle Miocene to Late Miocene, 8 to 14 million years old. About 5 mi of the line.
Gravel. Age: Quaternary, less than 2.6 million years old. About 4 mi of the line.
Age: Neoproterozoic to Cambrian, 487 to 1,000 million years old. About 2 mi of the line.
Orthogneiss, schist, amphibolite. Age: Neoarchean to Paleoproterozoic, 2.5 to 2.7 billion years old. About 0.6 mi of the line.
Age: Carboniferous to Permian, 252 to 324 million years old. About 0.3 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 Declo reaches the Pacific Ocean by way of Marsh Creek, the Snake and the Columbia: about 980 river miles.
Lakes on the way: Lake Umatilla, Brownlee Reservoir, Cove Arm Lake and Hells Canyon Reservoir.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Declo; river miles along the main stem, rounded.
Declo has a cold semi-arid climate. Summer afternoons average 88° in July; winter nights fall to about 21° in January. About 10 inches of rain fall in a normal year.
On November 14 Declo normally reaches 49° and falls to 27°. The record high is 71°, in 1999; the record low 5°, in 1978. The most rain on this date, 0.66 in, fell in 1952.
Normals 1991–2020 and records since 1917 from the Burley Area threaded record (Burley Municipal Airport, 7 miles west-northwest). NOAA, through RCC-ACIS.
