The Twin Falls 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; warmer
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75° on Nov. 13, 1999, the hottest reading for this week of the year since 1915. Next is 73° in 1934.
Twin Falls’s center stands about 3,730 ft above sea level. Within three miles the land runs from 3,140 ft to 3,880 ft, a difference of 740 ft: hilly country. The highest named summit within 15 miles is Berger Butte, about 4,700 ft, 13 miles southwest.
Under the town center the state geologic map shows Basalt (Pleistocene and Pliocene), from the Late Pliocene to Pleistocene, less than 3 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 15×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Basalt. Age: Late Pliocene to Pleistocene, less than 3 million years old. About 13 mi of the line.
Basalt. Age: Middle Miocene to Late Pliocene, 3 to 15 million years old. About 11 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 Twin Falls reaches the Pacific Ocean by way of the Perrine Coulee, the Snake and the Columbia: about 930 river miles.
Lakes on the way: Lake Umatilla, Brownlee Reservoir, Cove Arm Lake and Hells Canyon Reservoir.
240 miles of the trip are on the Snake.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Twin Falls; river miles along the main stem, rounded.
Twin Falls has a cold semi-arid climate. Summer afternoons average 90° in July; winter nights fall to about 22° in January. About 10 inches of rain fall in a normal year.
On November 14 Twin Falls normally reaches 48° and falls to 29°. The record high is 73°, in 1999; the record low 5°, in 1916. The most rain on this date, 0.83 in, fell in 2006.
Normals 1991–2020 and records since 1915 at Jerome, 12 miles north-northwest. NOAA, through RCC-ACIS.
