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 sunny
Mostly sunny; warmer
Mostly sunny
Partly cloudy
Mostly cloudy
Partly cloudy
Showers likely
74° on Nov. 14, 1990, the hottest reading for this week of the year since 1887. Next is 69° in 1953.
Harrison’s center stands about 1,180 ft above sea level. Within three miles the land runs from 1,160 ft to 1,220 ft, a difference of 60 ft: gently rolling country. The highest named summit within 15 miles is Mount Tom, about 1,370 ft, 14 miles northwest.
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 64×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Schist, slate. Age: Paleoproterozoic, 1.6 to 2.5 billion years old. About 10 mi of the line.
Orthogneiss, migmatite. Age: Paleoarchean to Mesoarchean, 2.8 to 3.6 billion years old. About 8 mi of the line.
Age: Paleoproterozoic, 1.6 to 1.8 billion years old. About 4 mi of the line.
Leucocratic-granitic. Age: Neoarchean, 2.5 to 2.8 billion years old. About 1 mi of the line.
Granitic. Age: Archean to Paleoproterozoic. About 1 mi of the line.
Granite. Age: Paleoproterozoic, 1.6 to 1.8 billion years old. About 0.7 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 Middle Fork Crow, the North Fork Crow, the Crow and the Mississippi: about 2,000 river miles.
Lake on the way: Lake Pepin.
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 warm-summer humid continental climate. Summer afternoons average 81° in July; winter nights fall to about 0° in January. About 30 inches of rain fall in a normal year.
On November 14 Harrison normally reaches 40° and falls to 22°. The record high is 74°, in 1990; the record low −6°, in 1940. The most rain on this date, 0.70 in, fell in 1951.
Normals 1991–2020 and records since 1887 at Litchfield, 14 miles east-southeast. NOAA, through RCC-ACIS.
