The Silvana 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.
Showers likely
Showers likely
Showers likely
Mostly sunny
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69° on Nov. 14, 2016, the hottest reading for this week of the year since 1894. Next is 67° in 1939.
Silvana’s center stands about 40 ft above sea level. Within three miles the land runs from 10 ft to 470 ft, a difference of 460 ft: hilly country. The highest named summit within 15 miles is Table Mountain, about 3,280 ft, 14 miles north-northeast.
Under the town center the state geologic map shows Alluvium (silt, sand), from the Holocene, less than 12,000 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 9×. 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 8 mi of the line.
Fine-detrital, coarse-detrital. Age: Pleistocene, less than 2.6 million years old. About 4 mi of the line.
Silt, sand. Age: Holocene, less than 12,000 years old. About 3 mi of the line.
Metasedimentary. Age: Devonian to Permian, 273 to 422 million years old. About 2 mi of the line.
Graywacke, argillite, siltstone. Age: Jurassic to Late Cretaceous, 66 to 202 million years old. About 2 mi of the line.
Fine-detrital, coarse-detrital. Age: Pleistocene, less than 2.6 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. 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 Silvana reaches the Pacific Ocean by way of the Stillaguamish and the West Pass: about 15 river miles.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Silvana; river miles along the main stem, rounded.
Silvana has a warm-summer Mediterranean climate. Summer afternoons average 76° in August; winter nights fall to about 34° in February. About 40 inches of rain fall in a normal year.
On November 14 Silvana normally reaches 53° and falls to 38°. The record high is 69°, in 2016; the record low 11°, in 1955. The most rain on this date, 1.30 in, fell in 1966.
Normals 1991–2020 and records since 1894 at Everett, 16 miles south. NOAA, through RCC-ACIS.
