The Martelle 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.
76° on Nov. 13, 1999, the hottest reading for this week of the year since 1892. Next is 75° in 1931.
Martelle’s center stands about 910 ft above sea level. Within three miles the land runs from 820 ft to 930 ft, a difference of 110 ft: gently rolling country.
Under the town center the state geologic map shows Gower Formation (dolostone, mudstone), from the Silurian, 425 to 434 million years old.
The section below crosses 3 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 60×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Dolostone, mudstone. Age: Silurian, 425 to 434 million years old. About 12 mi of the line.
Dolostone. Age: Silurian, 431 to 440 million years old. About 11 mi of the line.
Dolostone, limestone. Age: Middle Devonian, 384 to 394 million years old. About 1 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 Martelle reaches the Gulf of America by way of Elbow Creek, Big Creek, the Cedar River, the Iowa and the Mississippi: about 1,530 river miles.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Martelle; river miles along the main stem, rounded.
Martelle has a hot-summer humid continental climate. Summer afternoons average 86° in July; winter nights fall to about 13° in January. A normal year brings about 34 inches of snow; with the rain, that comes to about 39 inches of water.
On November 14 Martelle normally reaches 49° and falls to 30°. The record high is 73°, in 2025; the record low 4°, in 1940. The most rain on this date, 1.11 in, fell in 1902.
Normals 1991–2020 and records since 1892 at Cedar Rapids No. 1, 12 miles west. NOAA, through RCC-ACIS.