The Iona 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.
Sunny
Mostly sunny; warmer
Mostly sunny
Partly cloudy
Partly cloudy
Partly cloudy
Showers likely
79° on Nov. 14, 1999, the hottest reading for this week of the year since 1973. Next is 72° in 2001.
Iona’s center stands about 1,640 ft above sea level. Within three miles the land runs from 1,540 ft to 1,710 ft, a difference of 170 ft: gently rolling country.
Under the town center the state geologic map shows Undifferentiated (conglomerate, sandstone, mudstone), from the Late Cretaceous, 72 to 100 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 52×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Conglomerate, sandstone, mudstone. Age: Late Cretaceous, 72 to 100 million years old. About 16 mi of the line.
Quartzite, mudstone. Age: Paleoproterozoic, 1.6 to 2 billion years old. About 8 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 Iona reaches the Gulf of America by way of Lime Creek, the Des Moines and the Mississippi: about 1,870 river miles.
Lakes on the way: Roberts Creek and Big Creek Pounding Area.
1,330 miles of the trip are on the Mississippi.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Iona; river miles along the main stem, rounded.
Iona has a warm-summer humid continental climate. Summer afternoons average 81° in July; winter nights fall to about 4° in January. A normal year brings about 46 inches of snow; with the rain, that comes to about 30 inches of water.
On November 14 Iona normally reaches 41° and falls to 22°. The record high is 79°, in 1999; the record low −4°, in 2014. The most rain on this date, 1.12 in, fell in 2024.
Normals 1991–2020 and records since 1973 at Lake Wilson, 10 miles northwest. NOAA, through RCC-ACIS.
