The Harper 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
Showers likely
Partly cloudy
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Mostly sunny
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Showers likely
83° on Nov. 11, 1989, the hottest reading for this week of the year since 1896. Next is 83° in 1999.
Harper’s center stands about 1,430 ft above sea level. Within three miles the land runs from 1,380 ft to 1,470 ft, a difference of 90 ft: gently rolling country.
Under the town center the state geologic map shows Alluvium (sand, silt, clay), from the Pleistocene to Holocene, less than 2.6 million years old.
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 52×. 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, silt, clay. Age: Pleistocene to Holocene, less than 2.6 million years old. About 8 mi of the line.
Silt. Age: Pleistocene to Holocene, less than 2.6 million years old. About 6 mi of the line.
Sand, silt, clay. Age: Pleistocene, less than 2.6 million years old. About 6 mi of the line.
Siltstone, sandstone, shale. Age: Permian, 252 to 299 million years old. About 4 mi of the line.
Shale. Age: Permian, 252 to 299 million years old. About 0.6 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 Harper reaches the Gulf of America by way of Sand Creek, the Chikaskia, the Salt Fork Arkansas, the Arkansas and the Mississippi: about 1,330 river miles.
Lakes on the way: Murray Lake and Ozark Lake.
600 miles of the trip are on the Mississippi.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Harper; river miles along the main stem, rounded.
Harper has a humid subtropical climate. Summer afternoons average 93° in July; winter nights fall to about 22° in January. A normal year brings about 11 inches of snow; with the rain, that comes to about 33 inches of water.
On November 14 Harper normally reaches 58° and falls to 35°. The record high is 77°, in 1973; the record low 9°, in 1940. The most rain on this date, 2.80 in, fell in 1931.
Normals 1991–2020 and records since 1896 at Anthony, 9 miles south. NOAA, through RCC-ACIS.
