The Lake Ann 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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70° on Nov. 17, 2016, the hottest reading for this week of the year since 1959. Next is 67° in 1971.
Lake Ann’s center stands about 850 ft above sea level. Within three miles the land runs from 790 ft to 990 ft, a difference of 200 ft: rolling country. The highest named summit within 15 miles is Warner Hill, about 1,160 ft, 3 miles north-northwest.
Under the town center the state geologic map shows Ellsworth Shale, from the Late Devonian, 359 to 384 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 29×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Shale. Age: Late Devonian, 359 to 384 million years old. About 16 mi of the line.
Black-shale. Age: Late Devonian, 359 to 384 million years old. About 6 mi of the line.
Limestone. Age: Middle Devonian, 384 to 394 million years old. About 0.9 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 Lake Ann reaches Lake Michigan by way of the Platte: about 25 river miles. From there it moves on through the Great Lakes, over Niagara Falls and down the St. Lawrence to the Atlantic.
Lake on the way: Platte Lake.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Lake Ann; river miles along the main stem, rounded.
Lake Ann has a warm-summer humid continental climate. Summer afternoons average 80° in July; winter nights fall to about 16° in January. A normal year brings about 143 inches of snow; with the rain, that comes to about 36 inches of water.
On November 14 Lake Ann normally reaches 45° and falls to 31°. The record high is 62°, in 2009; the record low 15°, in 1986. The most rain on this date, 0.88 in, fell in 1969.
Normals 1991–2020 and records since 1959 at Maple City 1 E, 9 miles north. NOAA, through RCC-ACIS.
