The Alder 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
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Partly cloudy
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70° on Nov. 12, 1999, the hottest reading for this week of the year since 1893. Next is 68° in 1990.
Alder’s center stands about 5,120 ft above sea level. Within three miles the land runs from 5,040 ft to 6,030 ft, a difference of 990 ft: steep hill country. The highest named summit within 15 miles is Thompson Peak, about 10,330 ft, 15 miles north-northeast.
Under the town center the state geologic map shows Gravel, from the Pleistocene to Holocene, less than 1.8 million years old.
The section below crosses 9 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 5×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Andesite, basalt. Age: Tertiary, 2.6 to 66 million years old. About 5 mi of the line.
Gneiss. Age: Archean. About 5 mi of the line.
Unconsolidated. Age: Pleistocene to Holocene, less than 1.8 million years old. About 4 mi of the line.
Age: Pleistocene to Holocene, less than 1.8 million years old. About 4 mi of the line.
Limestone, dolostone, shale. Age: Early Mississippian to Permian, 252 to 359 million years old. About 3 mi of the line.
Age: Archean. 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. 3 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 Alder reaches the Gulf of America by way of the Ruby, the Beaverhead, the Jefferson, the Missouri and the Mississippi: about 3,590 river miles.
Lakes on the way: Lake Oahe, Lake Sakakawea, Lake Fort Peck and Lake Sharpe.
1,170 miles of the trip are on the Mississippi.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Alder; river miles along the main stem, rounded.
Alder has a warm-summer humid continental climate. Summer afternoons average 83° in July; winter nights fall to about 14° in December. A normal year brings about 65 inches of snow; with the rain, that comes to about 16 inches of water.
On November 14 Alder normally reaches 44° and falls to 22°. The record high is 68°, in 1999; the record low −14°, in 1955. The most rain on this date, 0.44 in, fell in 1996.
Normals 1991–2020 and records since 1893 at Virginia City, 8 miles east-southeast, 710 ft higher. NOAA, through RCC-ACIS.
