The Alta 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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60° on Nov. 12, 1999, the hottest reading for this week of the year since 1905. Next is 60° in 2016.
Alta’s center stands about 8,580 ft above sea level. Within three miles the land runs from 7,780 ft to 10,890 ft, a difference of 3,110 ft: mountain country. The highest named summit within 15 miles is Mount Timpanogos, about 11,560 ft, 14 miles south.
The section below crosses 11 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 3×. 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 7 mi of the line.
Arenite. Age: Neoproterozoic, 542 to 1,000 million years old. About 7 mi of the line.
Clay. Age: Pleistocene, less than 2.6 million years old. About 3 mi of the line.
Limestone. Age: Early Mississippian, 347 to 359 million years old. About 2 mi of the line.
Arenite. Age: Early Cambrian to Middle Cambrian, 497 to 542 million years old. About 2 mi of the line.
Granodiorite. Age: Middle Eocene to Early Oligocene, 30 to 42 million years old. About 2 mi of the line.
From the USGS State Geologic Map Compilation (Horton and others, 2017), the states’ geologic maps joined at a common scale. 5 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 Alta reaches Great Salt Lake by way of Little Cottonwood Creek and the Jordan: about 40 river miles. Great Salt Lake has no outlet to the sea: the water leaves only by evaporating or soaking into the ground.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Alta; river miles along the main stem, rounded.
Alta has a dry-summer warm-summer continental climate. Summer afternoons average 73° in July; winter nights fall to about 14° in December. A normal year brings about 458 inches of snow; with the rain, that comes to about 47 inches of water.
On November 14 Alta normally reaches 38° and falls to 21°. The record high is 60°, in 1999; the record low 1°, in 1994. The most rain on this date, 2.43 in, fell in 1950.
Normals 1991–2020 and records since 1905 at Alta, here, 130 ft higher. NOAA, through RCC-ACIS.
