The Opal 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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Partly cloudy; cooler
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65° on Nov. 15, 2016, the hottest reading for this week of the year since 1990. Next is 64° in 1999.
Opal’s center stands about 6,660 ft above sea level. Within three miles the land runs from 6,610 ft to 6,920 ft, a difference of 310 ft: rolling country. The highest named summit within 15 miles is Quealy Peak, about 8,010 ft, 10 miles west-northwest.
Under the town center the state geologic map shows Alluvium and Colluvium (clay, silt, sand), from the Pleistocene to Holocene, less than 2.6 million years old.
The section below crosses 8 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 17×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Sandstone, claystone. Age: Eocene, 34 to 56 million years old. About 12 mi of the line.
Shale, sandstone. Age: Late Cretaceous, 66 to 100 million years old. About 3 mi of the line.
Sandstone, shale, marlstone. Age: Eocene, 34 to 56 million years old. About 2 mi of the line.
Oil-shale, marlstone, mudstone. Age: Eocene, 34 to 56 million years old. About 2 mi of the line.
Clay, silt, sand. Age: Pleistocene to Holocene, less than 2.6 million years old. About 2 mi of the line.
Oil-shale, marlstone. Age: Eocene, 34 to 56 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. 2 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 Opal reaches the Gulf of California by way of the Hams Fork, the Blacks Fork, the Green River and the Colorado: about 1,580 river miles.
Lakes on the way: Lake Mead, Lake Powell, Flaming Gorge Reservoir and Lake Mohave.
410 miles of the trip are on the Green River.
Seldom reaches the sea. Dams and canals now take nearly all of the Colorado before its old delta in Mexico.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Opal; river miles along the main stem, rounded.
Opal has a warm-summer humid continental climate. Summer afternoons average 83° in July; winter nights fall to about 2° in January. A normal year brings about 50 inches of snow; with the rain, that comes to about 9 inches of water.
On November 14 Opal normally reaches 43° and falls to 14°. The record high is 64°, in 1999; the record low 0°, in 2009. The most rain on this date, 0.22 in, fell in 2006.
Normals 1991–2020 and records since 1990 at Kemmerer 2 N, 11 miles west-northwest, 280 ft higher. NOAA, through RCC-ACIS.
