The Sunnybrook Colony 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
Mostly cloudy
Chance of showers; cooler
Partly cloudy
Mostly cloudy
Partly cloudy
78° on Nov. 12, 1999, the hottest reading for this week of the year since 1952. Next is 73° in 1990.
Sunnybrook Colony’s center stands about 3,070 ft above sea level. Within three miles the land runs from 2,930 ft to 3,360 ft, a difference of 430 ft: hilly country. The highest named summit within 15 miles is Goose Bill Butte, about 3,760 ft, 7 miles south-southwest.
Under the town center the state geologic map shows Claggett Formation (shale), from the Late Cretaceous, 72 to 84 million years old.
The section below crosses 6 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 25×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Sandstone, sandstone-mudstone. Age: Late Cretaceous, 72 to 87 million years old. About 12 mi of the line.
Shale. Age: Late Cretaceous, 72 to 84 million years old. About 7 mi of the line.
Sandstone, siltstone, shale. Age: Late Cretaceous, 84 to 87 million years old. About 3 mi of the line.
Gravel, sand, silt. Age: Pleistocene to Holocene, less than 1.8 million years old. About 1 mi of the line.
Age: Pleistocene to Holocene, less than 1.8 million years old. About 0.8 mi of the line.
Sandstone, shale. Age: Late Cretaceous, 72 to 84 million years old. About 0.3 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 Sunnybrook Colony reaches the Gulf of America by way of the Marias, the Missouri and the Mississippi: about 3,240 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 Sunnybrook Colony; river miles along the main stem, rounded.
Sunnybrook Colony has a cold semi-arid climate. Summer afternoons average 85° in July; winter nights fall to about 8° in January. About 10 inches of rain fall in a normal year.
On November 14 Sunnybrook Colony normally reaches 44° and falls to 22°. The record high is 73°, in 2025; the record low −10°, in 1959. The most rain on this date, 0.21 in, fell in 1988.
Normals 1991–2020 and records since 1952 at Tiber Dam, 20 miles west-northwest, 160 ft lower. NOAA, through RCC-ACIS.
