The Blacktail 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.
Partly cloudy
Partly cloudy
Partly cloudy
Mostly cloudy
Chance of showers; cooler
Mostly cloudy
Chance of showers
75° on Nov. 12, 1999, the hottest reading for this week of the year since 1894. Next is 68° in 1934.
Blacktail’s center stands about 2,080 ft above sea level. Within three miles the land runs from 2,000 ft to 2,320 ft, a difference of 320 ft: rolling country. The highest named summit within 15 miles is Bull Butte, about 2,570 ft, 15 miles west-southwest.
Under the town center the state geologic map shows Sentinel Butte Formation (siltstone, claystone, sandstone), from the Paleocene, 56 to 66 million years old.
The section below crosses 2 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 35×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Siltstone, claystone, sandstone. Age: Paleocene, 56 to 66 million years old. About 21 mi of the line.
Claystone, siltstone. Age: Paleocene, 56 to 66 million years old. About 4 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 Blacktail reaches the Gulf of America by way of Blacktail Creek, the Little Muddy, the Missouri and the Mississippi: about 2,750 river miles.
Lakes on the way: Lake Oahe, Lake Sakakawea, Lake Sharpe and Lake Francis Case.
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 Blacktail; river miles along the main stem, rounded.
Blacktail has a cold semi-arid climate. Summer afternoons average 84° in July; winter nights fall to about 1° in January. A normal year brings about 48 inches of snow; with the rain, that comes to about 15 inches of water.
On November 14 Blacktail normally reaches 39° and falls to 18°. The record high is 67°, in 1899; the record low −15°, in 2014. The most rain on this date, 0.26 in, fell in 1988.
Normals 1991–2020 and records since 1894 from the Williston Area threaded record (Williston Sloulin Field, 18 miles south-southeast, 180 ft lower). NOAA, through RCC-ACIS.
