The Ephraim 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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72° on Nov. 12, 1999, the hottest reading for this week of the year since 1949. Next is 71° in 2016.
Ephraim’s center stands about 5,550 ft above sea level. Within three miles the land runs from 5,420 ft to 6,880 ft, a difference of 1,460 ft: steep hill country. The highest named summit within 15 miles is South Tent Mountain, about 11,270 ft, 12 miles east.
Under the town center the state geologic map shows Alluvium and colluvium (unconsolidated), from the Quaternary, 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 4×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Unconsolidated. Age: Quaternary, less than 2.6 million years old. About 9 mi of the line.
Limestone, mixed-clastic. Age: Late Paleocene to Early Eocene, 48 to 59 million years old. About 6 mi of the line.
Limestone. Age: Late Paleocene to Early Eocene, 48 to 59 million years old. About 4 mi of the line.
Siltstone-mudstone. Age: Late Cretaceous to Paleocene, 56 to 100 million years old. About 3 mi of the line.
Shale, marlstone. Age: Early Eocene to Late Eocene, 34 to 56 million years old. About 1 mi of the line.
Siltstone-mudstone, sandstone. Age: Late Cretaceous to Early Eocene, 48 to 84 million years old. About 0.9 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 Ephraim reaches Sevier Lake by way of Ephraim Creek, the San Pitch and the Sevier: about 220 river miles. Sevier Lake has no outlet to the sea: the water leaves only by evaporating or soaking into the ground.
180 miles of the trip are on the Sevier.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Ephraim; river miles along the main stem, rounded.
Ephraim has a cold semi-arid climate. Summer afternoons average 91° in July; winter nights fall to about 11° in January. A normal year brings about 20 inches of snow; with the rain, that comes to about 12 inches of water.
On November 14 Ephraim normally reaches 52° and falls to 21°. The record high is 72°, in 1999; the record low 8°, in 1964. The most rain on this date, 0.46 in, fell in 1951.
Normals 1991–2020 and records since 1949 at Ephraim, here. NOAA, through RCC-ACIS.
