The Harrison 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.
Mostly cloudy
Mostly sunny; warmer
Partly cloudy
Partly cloudy
Mostly sunny; cooler
Partly cloudy
Showers likely
−15° on Nov. 13, 2014, the coldest reading for this week of the year since 1994. Next is −8° in 2000.
Harrison’s center stands about 4,870 ft above sea level. Within three miles the land runs from 4,690 ft to 4,990 ft, a difference of 300 ft: rolling country.
Under the town center the state geologic map shows Arikaree Group (sand, volcanic), from the Late Oligocene to Miocene, 5.3 to 28 million years old.
The section below crosses 3 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 18×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Sand, volcanic. Age: Late Oligocene to Miocene, 5.3 to 28 million years old. About 18 mi of the line.
Clay. Age: Early Oligocene to Late Oligocene, 23 to 34 million years old. About 4 mi of the line.
Shale. Age: Late Cretaceous, 66 to 100 million years old. About 2 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 Harrison reaches the Gulf of America by way of the Niobrara, the Missouri and the Mississippi: about 2,460 river miles.
Lake on the way: Lewis and Clark Lake.
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 Harrison; river miles along the main stem, rounded.
Harrison has a cold semi-arid climate. Summer afternoons average 87° in July; winter nights fall to about 14° in January. A normal year brings about 53 inches of snow; with the rain, that comes to about 15 inches of water.
On November 14 Harrison normally reaches 47° and falls to 22°. The record high is 74°, in 1999; the record low −14°, in 2014. The most rain on this date, 0.15 in, fell in 2008.
Normals 1991–2020 and records since 1994 at Torrington 29 N, 20 miles southwest. NOAA, through RCC-ACIS.
