The South Lebanon 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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70° on Nov. 12, 1981, the hottest reading for this week of the year since 1973. Next is 69° in 1976.
South Lebanon’s center stands about 370 ft above sea level. Within three miles the land runs from 330 ft to 1,280 ft, a difference of 950 ft: steep hill country. The highest named summit within 15 miles is Keel Mountain, about 2,810 ft, 14 miles east.
Under the town center the state geologic map shows Terrace, pediment, and lag gravels (gravel, boulders, clay), from the Pleistocene to Holocene, less than 2.6 million years old.
The section below crosses 7 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 12×. 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, basaltic-andesite. Age: Oligocene to Miocene, 5.3 to 34 million years old. About 7 mi of the line.
Clay, silt, sand. Age: Pleistocene, less than 2.6 million years old. About 6 mi of the line.
Sand, gravel, silt. Age: Holocene, less than 12,000 years old. About 5 mi of the line.
Gravel, boulders, clay. Age: Pleistocene to Holocene, less than 2.6 million years old. About 2 mi of the line.
Sandstone, siltstone. Age: Late Eocene to Oligocene, 23 to 38 million years old. About 2 mi of the line.
Hypabyssal-basalt, hypabyssal-andesite, hypabyssal-basaltic-andesite. Age: Oligocene to Pliocene, 2.6 to 34 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. 1 smaller unit 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 South Lebanon reaches the Pacific Ocean by way of Oak Creek, the Calapooia, the Willamette and the Columbia: about 240 river miles.
Lake on the way: Willamette Falls Hydroelectric Power Reservoir.
100 miles of the trip are on the Columbia.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of South Lebanon; river miles along the main stem, rounded.
South Lebanon has a warm-summer Mediterranean climate. Summer afternoons average 82° in August; winter nights fall to about 33° in January. About 57 inches of rain fall in a normal year, with about 2 inches of snow.
On November 14 South Lebanon normally reaches 52° and falls to 37°. The record high is 69°, in 1999; the record low 18°, in 1978. The most rain on this date, 1.86 in, fell in 2014.
Normals 1991–2020 and records since 1973 at Lacomb 3 NNE, 12 miles northeast, 150 ft higher. NOAA, through RCC-ACIS.
