The Summit 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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3.67 inches of rain fell in two days, the most for this week of the year since records began in 1941. The next wettest, 3.42 inches, fell in 2001.
Summit’s center stands about 470 ft above sea level. Within three miles the land runs from 30 ft to 500 ft, a difference of 470 ft: hilly country. The highest named summit within 15 miles is Spar Pole Hill, about 1,900 ft, 13 miles southeast.
Under the town center the state geologic map shows Younger glacial drift (fine-detrital, coarse-detrital), from the Pleistocene, less than 2.6 million years old.
The section below crosses 4 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 23×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Fine-detrital, coarse-detrital. Age: Pleistocene, less than 2.6 million years old. About 16 mi of the line.
Fine-detrital, coarse-detrital. Age: Pleistocene, less than 2.6 million years old. About 2 mi of the line.
Silt, sand. Age: Holocene, less than 12,000 years old. About 2 mi of the line.
Fine-detrital, coarse-detrital. Age: Late Pliocene to Pleistocene, less than 3.6 million years old. About 0.5 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 Summit reaches Puget Sound and the Pacific Ocean by way of Clear Creek and the Puyallup: about 7 river miles.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Summit; river miles along the main stem, rounded.
Summit has a warm-summer Mediterranean climate. Summer afternoons average 77° in August; winter nights fall to about 33° in January. A normal year brings about 6 inches of snow; with the rain, that comes to about 45 inches of water.
On November 14 Summit normally reaches 51° and falls to 36°. The record high is 63°, in 1975; the record low 4°, in 1955. The most rain on this date, 2.35 in, fell in 2001.
Normals 1991–2020 and records since 1941 at Mcmillin Reservoir, 5 miles east-southeast, 100 ft higher. NOAA, through RCC-ACIS.
