The Derby 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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80° on Nov. 17, 2016, the hottest reading for this week of the year since 1948. Next is 79° in 1990.
Derby’s center stands about 5,130 ft above sea level. Within three miles the land runs from 5,040 ft to 5,240 ft, a difference of 200 ft: gently rolling country. The highest named summit within 15 miles is Inspiration Point, about 5,420 ft, 8 miles west-southwest.
The section below crosses 5 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 33×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Sandstone, mudstone, conglomerate. Age: Late Cretaceous to Paleocene, 56 to 100 million years old. About 9 mi of the line.
Sand, silt. Age: Quaternary, less than 2.6 million years old. About 7 mi of the line.
Arkose, shale, mudstone. Age: Late Cretaceous to Paleocene, 56 to 100 million years old. About 5 mi of the line.
Unconsolidated. Age: Quaternary, less than 2.6 million years old. About 2 mi of the line.
Gravel, unconsolidated. Age: Pleistocene, less than 0.5 million 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.
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 Derby reaches the Gulf of America by way of the South Platte, the Platte, the Missouri and the Mississippi: about 2,390 river miles.
1,170 miles of the trip are on the Mississippi.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Derby; river miles along the main stem, rounded.
Derby has a cold semi-arid climate. Summer afternoons average 90° in July; winter nights fall to about 18° in January. A normal year brings about 49 inches of snow; with the rain, that comes to about 15 inches of water.
On November 14 Derby normally reaches 56° and falls to 26°. The record high is 79°, in 1990; the record low −5°, in 2014. The most rain on this date, 0.60 in, fell in 1994.
Normals 1991–2020 and records since 1948 at Denver-Central Park, 6 miles south-southeast, 150 ft higher. NOAA, through RCC-ACIS.
