The Hemlock 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.
Chance of showers
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78° on Nov. 11, 2020, the hottest reading for this week of the year since 1898. Next is 73° in 2012.
Hemlock’s center stands about 910 ft above sea level. Within three miles the land runs from 900 ft to 1,550 ft, a difference of 650 ft: hilly country. The highest named summit within 15 miles is Gannett Hill, about 2,320 ft, 12 miles east-southeast.
Under the town center the state geologic map shows Genesee Group (shale), from the Late Devonian, 359 to 384 million years old.
The section below crosses 12 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 11×. 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, siltstone. Age: Late Devonian, 359 to 384 million years old. About 5 mi of the line.
Shale. Age: Middle Devonian, 384 to 388 million years old. About 4 mi of the line.
Shale. Age: Late Devonian, 359 to 384 million years old. About 3 mi of the line.
Shale, siltstone. Age: Late Devonian, 359 to 384 million years old. About 3 mi of the line.
Shale. Age: Late Devonian, 359 to 384 million years old. About 2 mi of the line.
Shale. Age: Late Devonian, 359 to 384 million 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. 6 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 Hemlock reaches Lake Ontario by way of the Hemlock Outlet, Honeoye Creek and the Genesee: about 60 river miles. From the lake it goes down the St. Lawrence to the Atlantic.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Hemlock; river miles along the main stem, rounded.
Hemlock has a warm-summer humid continental climate. Summer afternoons average 81° in July; winter nights fall to about 16° in January. About 37 inches of rain fall in a normal year.
On November 14 Hemlock normally reaches 49° and falls to 33°. The record high is 69°, in 1994; the record low 12°, in 1983. The most rain on this date, 0.67 in, fell in 1997.
Normals 1991–2020 and records since 1898 at Hemlock, here. NOAA, through RCC-ACIS.
