The Portland 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
Mostly cloudy
Chance of showers
Mostly cloudy
Chance of showers
70° on Nov. 12, 2005, the hottest reading for this week of the year since 1893. Next is 68° in 1953.
Portland’s center stands about 990 ft above sea level. Within three miles the land runs from 950 ft to 1,020 ft, a difference of 70 ft: gently rolling country.
Under the town center the state geologic map shows Belle Fourche Formation (shale), from the Late Cretaceous, 66 to 100 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 64×. 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. Age: Late Cretaceous, 66 to 100 million years old. About 13 mi of the line.
Shale. Age: Late Cretaceous, 66 to 100 million years old. About 7 mi of the line.
Shale, sandstone. Age: Early Cretaceous to Late Cretaceous, 66 to 145 million years old. About 3 mi of the line.
Shale. Age: Late Cretaceous, 66 to 100 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 Portland reaches Hudson Bay by way of the Goose, the Red River of the North and the Nelson: about 1,070 river miles. Past the border it runs north through Canada to Hudson Bay.
Lake on the way: Lake Winnipeg.
400 miles of the trip are on the Nelson.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Portland; river miles along the main stem, rounded.
Portland has a warm-summer humid continental climate. Summer afternoons average 80° in July; winter nights fall to about −4° in January. About 24 inches of rain fall in a normal year.
On November 14 Portland normally reaches 37° and falls to 18°. The record high is 65°, in 1953; the record low −15°, in 1919. The most rain on this date, 0.90 in, fell in 1922.
Normals 1991–2020 and records since 1893 at Mayville, here. NOAA, through RCC-ACIS.
