The Iron Mountain 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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2° on Nov. 15, 2014, the coldest reading for this week of the year since 1996. Next is 3° in 2019.
Iron Mountain’s center stands about 1,140 ft above sea level. Within three miles the land runs from 970 ft to 1,500 ft, a difference of 530 ft: hilly country. The highest named summit within 15 miles is Millie Hill, about 1,590 ft, 1 miles east.
Under the town center the state geologic map shows Baraga Group; Michigamme Formation, undivided (mixed-clastic, metagraywacke), from the Paleoproterozoic, 1.6 to 2.5 billion years old.
The section below crosses 7 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 30×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Mixed-clastic, metagraywacke. Age: Paleoproterozoic, 1.6 to 2.5 billion years old. About 8 mi of the line.
Metagraywacke. Age: Paleoproterozoic, 1.6 to 2.5 billion years old. About 5 mi of the line.
Metasedimentary, metavolcanic. Age: Paleoproterozoic, 1.6 to 2.5 billion years old. About 4 mi of the line.
Basalt, basaltic-andesite. Age: Paleoproterozoic, 1.6 to 2.5 billion years old. About 3 mi of the line.
Gneiss, amphibolite, migmatite. Age: Paleoarchean to Neoarchean, 2.5 to 3.6 billion years old. About 2 mi of the line.
Dacite. Age: Paleoproterozoic, 1.8 to 1.9 billion 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. 1 smaller unit along the line are not listed.
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 Iron Mountain reaches Lake Michigan by way of the Menominee: about 100 river miles. From there it moves on through the Great Lakes, over Niagara Falls and down the St. Lawrence to the Atlantic.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Iron Mountain; river miles along the main stem, rounded.
Iron Mountain has a warm-summer humid continental climate. Summer afternoons average 80° in July; winter nights fall to about 6° in January. About 21 inches of rain fall in a normal year.
On November 14 Iron Mountain normally reaches 41° and falls to 24°. The record high is 59°, in 2001; the record low 4°, in 2014. The most rain on this date, 0.22 in, fell in 2020.
Normals 1991–2020 and records since 1996 at Iron Mountain Ford Airport, 2 miles west-southwest. NOAA, through RCC-ACIS.
