The Dallas 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.
67° on Nov. 16, 1976, the hottest reading for this week of the year since 1928. Next is 66° in 1939.
Dallas’s center stands about 320 ft above sea level. Within three miles the land runs from 210 ft to 740 ft, a difference of 530 ft: hilly country. The highest named summit within 15 miles is Laurel Mountain, about 3,600 ft, 13 miles west.
The section below crosses 6 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 6×. 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: Paleocene to Middle Eocene, 38 to 66 million years old. About 10 mi of the line.
Clay, silt, sand. Age: Pleistocene, less than 2.6 million years old. About 8 mi of the line.
Sand, gravel, silt. Age: Holocene, less than 12,000 years old. About 5 mi of the line.
Siltstone. Age: Middle Eocene to Late Eocene, 34 to 48 million years old. About 1 mi of the line.
Gravel, boulders, clay. Age: Pleistocene to Holocene, less than 2.6 million years old. About 0.3 mi of the line.
Gabbro. Age: Oligocene, 23 to 34 million years old. About 0.3 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 Dallas reaches the Pacific Ocean by way of Rickreall Creek, the Willamette and the Columbia: about 200 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 Dallas; river miles along the main stem, rounded.
Dallas has a warm-summer Mediterranean climate. Summer afternoons average 83° in July; winter nights fall to about 35° in January. About 48 inches of rain fall in a normal year.
On November 14 Dallas normally reaches 52° and falls to 39°. The record high is 64°, in 2001; the record low 15°, in 1978. The most rain on this date, 2.00 in, fell in 1941.
Normals 1991–2020 and records since 1928 at Dallas 2 NE, here. NOAA, through RCC-ACIS.