The Sullivan 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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9° on Nov. 17, 1959, the coldest reading for this week of the year since 1896. Next is 11° in 1911.
Sullivan’s center stands about 670 ft above sea level. Within three miles the land runs from 650 ft to 730 ft, a difference of 80 ft: gently rolling country.
Under the town center the state geologic map shows Michigan Formation (shale), from the Carboniferous, 324 to 359 million years old.
The section below crosses 2 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 63×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Sandstone. Age: Carboniferous, 324 to 359 million years old. About 12 mi of the line.
Shale. Age: Carboniferous, 324 to 359 million years old. About 12 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 Sullivan reaches Lake Michigan by way of Norris Creek and the Grand River: about 16 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 Sullivan; river miles along the main stem, rounded.
Sullivan has a hot-summer humid continental climate. Summer afternoons average 82° in July; winter nights fall to about 21° in January. A normal year brings about 87 inches of snow; with the rain, that comes to about 35 inches of water.
On November 14 Sullivan normally reaches 48° and falls to 34°. The record high is 64°, in 1964; the record low 15°, in 1995. The most rain on this date, 1.76 in, fell in 1957.
Normals 1991–2020 and records since 1896 from the Muskegon Area threaded record (Muskegon County Airport, 9 miles west). NOAA, through RCC-ACIS.
