The Broad Top 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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11° on Nov. 14, 1986, the coldest reading for this week of the year since 1948. Next is 12° in 1959.
Broad Top’s center stands about 1,770 ft above sea level. Within three miles the land runs from 980 ft to 2,400 ft, a difference of 1,420 ft: steep hill country. The highest named summit within 15 miles is Coot Hill, about 2,480 ft, 6 miles west-northwest.
The section below crosses 17 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 12×. 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, siltstone, shale. Age: Late Devonian, 359 to 384 million years old. About 4 mi of the line.
Shale. Age: Carboniferous, 299 to 324 million years old. About 3 mi of the line.
Sandstone. Age: Carboniferous, 299 to 324 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.
Shale, siltstone, sandstone. Age: Carboniferous, 324 to 359 million years old. About 2 mi of the line.
Siltstone. Age: Late Devonian, 359 to 384 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. 11 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 Broad Top reaches Chesapeake Bay and the Atlantic Ocean by way of Longs Run, the Raystown Branch Juniata, the Juniata and the Susquehanna: about 230 river miles.
Lakes on the way: Lake Aldred and Raystown Lake.
90 miles of the trip are on the Juniata.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Broad Top; river miles along the main stem, rounded.
Broad Top has a hot-summer humid continental climate. Summer afternoons average 83° in July; winter nights fall to about 21° in January. About 37 inches of rain fall in a normal year.
On November 14 Broad Top normally reaches 51° and falls to 34°. The record high is 73°, in 1993; the record low 11°, in 1986. The most rain on this date, 2.25 in, fell in 1972.
Normals 1991–2020 and records since 1948 at Altoona Blair County Airport, 13 miles north-northwest, 300 ft lower. NOAA, through RCC-ACIS.
