The Riverside 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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80° on Nov. 12, 1999, the hottest reading for this week of the year since 1892. Next is 75° in 1908.
Riverside’s center stands about 1,280 ft above sea level. Within three miles the land runs from 1,080 ft to 1,520 ft, a difference of 440 ft: hilly country. The highest named summit within 15 miles is Emigrant Hill, about 3,870 ft, 12 miles east-southeast.
The section below crosses 5 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 7×. 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: Middle Miocene, 12 to 16 million years old. About 11 mi of the line.
Silt, sand. Age: Pleistocene to Holocene, less than 2.6 million years old. About 5 mi of the line.
Basalt. Age: Early Miocene to Middle Miocene, 12 to 23 million years old. About 4 mi of the line.
Sand, gravel, silt. Age: Holocene, less than 12,000 years old. About 3 mi of the line.
Sandstone, siltstone, mudstone. Age: Miocene to Pliocene, 2.6 to 23 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.
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 Riverside reaches the Pacific Ocean by way of the Umatilla and the Columbia: about 340 river miles.
Lake on the way: Lake Umatilla.
210 miles of the trip are on the Columbia.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Riverside; river miles along the main stem, rounded.
Riverside has a cold semi-arid climate. Summer afternoons average 89° in July; winter nights fall to about 28° in January. A normal year brings about 16 inches of snow; with the rain, that comes to about 13 inches of water.
On November 14 Riverside normally reaches 50° and falls to 33°. The record high is 72°, in 1953; the record low −4°, in 1955. The most rain on this date, 0.53 in, fell in 1963.
Normals 1991–2020 and records since 1892 from the Pendleton Area threaded record (Pendleton E Or Regional Airport, 5 miles west-northwest, 200 ft higher). NOAA, through RCC-ACIS.
