The Gem Lake 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
Partly cloudy
Showers likely
−7° on Nov. 11, 1995, the coldest reading for this week of the year since 1981. Next is 3° in 1996.
Gem Lake’s center stands about 970 ft above sea level. Within three miles the land runs from 860 ft to 1,040 ft, a difference of 180 ft: gently rolling country.
Under the town center the state geologic map shows Lower Ordovician (dolostone, sandstone), from the Early Ordovician, 471 to 487 million years old.
The section below crosses 4 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 49×. 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, limestone, sandstone. Age: Middle Ordovician to Late Ordovician, 445 to 471 million years old. About 12 mi of the line.
Dolostone, sandstone. Age: Early Ordovician, 471 to 487 million years old. About 10 mi of the line.
Sandstone, siltstone, shale. Age: Cambrian, 487 to 497 million years old. About 1 mi of the line.
Sandstone. Age: Cambrian, 487 to 542 million years old. About 0.6 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 Gem Lake reaches the Gulf of America by way of the Mississippi: about 1,830 river miles.
Lake on the way: Lake Pepin.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Gem Lake; river miles along the main stem, rounded.
Gem Lake has a hot-summer humid continental climate. Summer afternoons average 83° in July; winter nights fall to about 8° in January. About 33 inches of rain fall in a normal year.
On November 14 Gem Lake normally reaches 43° and falls to 29°. The record high is 71°, in 1990; the record low 4°, in 1996. The most rain on this date, 0.13 in, fell in 1983.
Normals 1991–2020 and records since 1981 at Vadnais Lake, 3 miles west-southwest. NOAA, through RCC-ACIS.
