The Lyons 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.
Partly cloudy
Mostly sunny
Partly cloudy
Partly cloudy
Mostly sunny
Partly cloudy
Chance of showers
−14° on Nov. 11, 1950, the coldest reading for this week of the year since 1893. Next is −13° in 1916.
Lyons’s center stands about 5,350 ft above sea level. Within three miles the land runs from 5,190 ft to 6,560 ft, a difference of 1,370 ft: steep hill country. The highest named summit within 15 miles is Twin Sisters Mountain, about 11,360 ft, 14 miles west-northwest.
The section below crosses 12 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 5×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Alkali-feldspar-granite, granite. Age: Mesoproterozoic, 1 to 1.6 billion years old. About 9 mi of the line.
Shale. Age: Late Cretaceous, 66 to 100 million years old. About 4 mi of the line.
Sandstone. Age: Late Cretaceous, 66 to 100 million years old. About 2 mi of the line.
Unconsolidated. Age: Quaternary, less than 2.6 million years old. About 1 mi of the line.
Gravel, unconsolidated. Age: Pleistocene, less than 0.5 million years old. About 1 mi of the line.
Limestone, sandstone, conglomerate. Age: Carboniferous to Permian, 252 to 324 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. 6 smaller units along the line are not listed.
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 Lyons reaches the Gulf of America by way of North Saint Vrain Creek, Saint Vrain Creek, the South Platte, the Platte, the Missouri and the Mississippi: about 2,380 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 Lyons; river miles along the main stem, rounded.
Lyons has a cold semi-arid climate. Summer afternoons average 91° in July; winter nights fall to about 14° in January. About 15 inches of rain fall in a normal year.
On November 14 Lyons normally reaches 54° and falls to 24°. The record high is 78°, in 1999; the record low −6°, in 1940. The most rain on this date, 0.79 in, fell in 1994.
Normals 1991–2020 and records since 1893 at Longmont 2 ESE, 11 miles east-southeast, 400 ft lower. NOAA, through RCC-ACIS.
