The Merrillville 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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75° on Nov. 11, 2020, the hottest reading for this week of the year since 1963. Next is 74° in 1964.
Merrillville’s center stands about 680 ft above sea level. Within three miles the land runs from 620 ft to 720 ft, a difference of 100 ft: gently rolling country.
Under the town center the state geologic map shows Antrim Shale (black-shale), from the Devonian, 359 to 422 million years old.
The section below crosses 3 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.
Black-shale. Age: Devonian, 359 to 422 million years old. About 10 mi of the line.
Limestone, dolostone. Age: Devonian, 359 to 422 million years old. About 10 mi of the line.
Limestone, dolostone. Age: Silurian, 422 to 445 million 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.
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 Merrillville reaches Lake Michigan by way of Turkey Creek and the Portage-Burns Waterway: about 25 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 Merrillville; river miles along the main stem, rounded.
Merrillville has a hot-summer humid continental climate. Summer afternoons average 84° in July; winter nights fall to about 15° in January. A normal year brings about 30 inches of snow; with the rain, that comes to about 40 inches of water.
On November 14 Merrillville normally reaches 50° and falls to 31°. The record high is 73°, in 1999; the record low 11°, in 1976. The most rain on this date, 1.62 in, fell in 1972.
Normals 1991–2020 and records since 1963 at Lowell Wwtp, 16 miles south-southwest. NOAA, through RCC-ACIS.
