The Loomis 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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Loomis’s center stands about 1,260 ft above sea level. Within three miles the land runs from 1,170 ft to 3,970 ft, a difference of 2,800 ft: mountain country. The highest named summit within 15 miles is Chopaka Mountain, about 7,860 ft, 11 miles northwest.
Under the town center the state geologic map shows Glacial drift, undivided (sand, gravel), from the Pleistocene, less than 2.6 million years old.
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 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.
Granite. Age: Precambrian to Eocene. About 10 mi of the line.
Metasedimentary. Age: Permian, 252 to 299 million years old. About 7 mi of the line.
Sand, gravel. Age: Pleistocene, less than 2.6 million years old. About 3 mi of the line.
Gneiss. Age: Precambrian to Eocene. About 3 mi of the line.
Andesite, dacite. Age: Eocene to Oligocene, 23 to 56 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.
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 Loomis reaches the Pacific Ocean by way of Sinlahekin Creek, Palmer Creek, the Similkameen, the Okanogan and the Columbia: about 630 river miles.
Lake on the way: Lake Umatilla.
250 miles of the trip are on the Columbia.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Loomis; river miles along the main stem, rounded.
