The Confluence 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.
Mostly cloudy
Mostly cloudy
Mostly cloudy
Partly cloudy
Sunny
Mostly sunny
Mostly sunny
77° on Nov. 11, 2020, the hottest reading for this week of the year since 1946. Next is 75° in 1993.
Confluence’s center stands about 1,340 ft above sea level. Within three miles the land runs from 1,320 ft to 2,140 ft, a difference of 820 ft: hilly country. The highest named summit within 15 miles is Mount Davis, about 3,220 ft, 10 miles east.
Under the town center the state geologic map shows Glenshaw Formation (shale), from the Carboniferous, 299 to 324 million years old.
The section below crosses 10 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 10×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Sandstone. Age: Carboniferous, 299 to 324 million years old. About 8 mi of the line.
Shale. Age: Carboniferous, 299 to 324 million years old. About 5 mi of the line.
Sandstone, siltstone, shale. Age: Devonian to Carboniferous, 324 to 422 million years old. About 3 mi of the line.
Sandstone, shale. Age: Devonian to Carboniferous, 324 to 422 million years old. About 2 mi of the line.
Sandstone, conglomerate. Age: Carboniferous, 299 to 324 million years old. About 2 mi of the line.
Sandstone, shale. Age: Carboniferous, 299 to 324 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. 4 smaller units 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 Confluence reaches the Gulf of America by way of the Casselman, the Youghiogheny, the Monongahela, the Ohio and the Mississippi: about 2,040 river miles.
970 miles of the trip are on the Ohio.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Confluence; river miles along the main stem, rounded.
Confluence has a hot-summer humid continental climate. Summer afternoons average 84° in July; winter nights fall to about 19° in January. A normal year brings about 61 inches of snow; with the rain, that comes to about 47 inches of water.
On November 14 Confluence normally reaches 52° and falls to 30°. The record high is 74°, in 1989; the record low 7°, in 1986. The most rain on this date, 0.90 in, fell in 1972.
Normals 1991–2020 and records since 1946 at Confluence 1 SW Dam, here, 150 ft higher. NOAA, through RCC-ACIS.
