The Ottawa 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.
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83° on Nov. 13, 1999, the hottest reading for this week of the year since 1895. Next is 81° in 1956.
Ottawa’s center stands about 910 ft above sea level. Within three miles the land runs from 880 ft to 960 ft, a difference of 80 ft: gently rolling country. The highest named summit within 15 miles is Chippewa Hills, about 1,160 ft, 6 miles west-southwest.
Under the town center the state geologic map shows Alluvium (sand, silt, clay), from the Pleistocene to Holocene, less than 2.6 million years old.
The section below crosses 5 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, sandstone. Age: Carboniferous, 299 to 324 million years old. About 8 mi of the line.
Sand, silt, clay. Age: Pleistocene to Holocene, less than 2.6 million years old. About 8 mi of the line.
Shale, limestone. Age: Carboniferous, 299 to 324 million years old. About 4 mi of the line.
Limestone, shale. Age: Carboniferous, 299 to 324 million years old. About 4 mi of the line.
Limestone, shale. Age: Carboniferous, 299 to 324 million years old. About 0.7 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 Ottawa reaches the Gulf of America by way of Rock Creek, the Marais des Cygnes, the Osage, the Missouri and the Mississippi: about 1,710 river miles.
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 Ottawa; river miles along the main stem, rounded.
Ottawa has a hot-summer humid continental climate. Summer afternoons average 89° in July; winter nights fall to about 18° in January. A normal year brings about 9 inches of snow; with the rain, that comes to about 40 inches of water.
On November 14 Ottawa normally reaches 55° and falls to 32°. The record high is 79°, in 1964; the record low 9°, in 1959. The most rain on this date, 2.37 in, fell in 1931.
Normals 1991–2020 and records since 1895 at Ottawa, here. NOAA, through RCC-ACIS.
