The Black Hammer 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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71° on Nov. 14, 1999, the hottest reading for this week of the year since 1892. Next is 69° in 1917.
Black Hammer’s center stands about 1,170 ft above sea level. Within three miles the land runs from 840 ft to 1,260 ft, a difference of 420 ft: hilly country.
Under the town center the state geologic map shows Lower Ordovician (dolostone, sandstone), from the Early Ordovician, 471 to 487 million years old.
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 31×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Dolostone, sandstone. Age: Early Ordovician, 471 to 487 million years old. About 12 mi of the line.
Sandstone, siltstone, shale. Age: Middle Cambrian to Cambrian, 487 to 521 million years old. About 4 mi of the line.
Shale, limestone, sandstone. Age: Middle Ordovician to Late Ordovician, 445 to 471 million years old. About 4 mi of the line.
Dolostone, sandstone. Age: Early Ordovician to Late Ordovician, 454 to 487 million years old. About 2 mi of the line.
Dolostone, limestone. Age: Late Ordovician, 447 to 459 million years old. About 1 mi of the line.
Sandstone, siltstone, shale. Age: Cambrian, 487 to 497 million years old. About 1 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 Black Hammer reaches the Gulf of America by way of Riceford Creek, the South Fork Root, the Root and the Mississippi: about 1,710 river miles.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Black Hammer; river miles along the main stem, rounded.
Black Hammer has a warm-summer humid continental climate. Summer afternoons average 81° in July; winter nights fall to about 8° in January. A normal year brings about 45 inches of snow; with the rain, that comes to about 38 inches of water.
On November 14 Black Hammer normally reaches 43° and falls to 27°. The record high is 71°, in 1999; the record low −3°, in 1986. The most rain on this date, 1.40 in, fell in 1902.
Normals 1991–2020 and records since 1892 at Caledonia, 8 miles east. NOAA, through RCC-ACIS.
