The Erwin 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
Partly cloudy
Partly cloudy
Partly cloudy
Chance of showers
Showers likely
3.72 inches of rain fell in two days, the most for this week of the year since records began in 1901. The next wettest, 2.85 inches, fell in 1911.
Erwin’s center stands about 1,540 ft above sea level. Within three miles the land runs from 1,500 ft to 1,680 ft, a difference of 180 ft: gently rolling country. The highest named summit within 15 miles is Mount Zion, about 1,720 ft, 8 miles north-northwest.
Under the town center the state geologic map shows Puritan Quartz Monzonite (granite, granodiorite), from the Mesoarchean to Neoarchean, 2.6 to 2.9 billion years old.
The section below crosses 10 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.
Granite, granodiorite. Age: Mesoarchean to Neoarchean, 2.6 to 2.9 billion years old. About 9 mi of the line.
Granodiorite, granite. Age: Mesoarchean to Neoarchean, 2.6 to 2.9 billion years old. About 4 mi of the line.
Basalt. Age: Paleoproterozoic, 1.6 to 2.5 billion years old. About 2 mi of the line.
Gneiss, amphibolite. Age: Neoarchean, 2.5 to 2.8 billion years old. About 2 mi of the line.
Sandstone. Age: Mesoproterozoic, 1 to 1.6 billion years old. About 2 mi of the line.
Basalt. Age: Mesoproterozoic, 1.1 to 1.1 billion 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. 4 smaller units 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 Erwin reaches Lake Superior by way of the Black River: about 35 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 Erwin; river miles along the main stem, rounded.
Erwin has a warm-summer humid continental climate. Summer afternoons average 76° in July; winter nights fall to about 4° in January. A normal year brings about 186 inches of snow; with the rain, that comes to about 37 inches of water.
On November 14 Erwin normally reaches 38° and falls to 24°. The record high is 67°, in 1999; the record low −5°, in 1986. The most rain on this date, 0.74 in, fell in 2000.
Normals 1991–2020 and records since 1901 at Ironwood, 8 miles northwest, 110 ft lower. NOAA, through RCC-ACIS.
