The Au Sable 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.
Chance of showers
Mostly cloudy; warmer
Mostly cloudy
Mostly sunny
Mostly sunny
Partly cloudy
Partly cloudy
1° on Nov. 13, 2019, the coldest reading for this week of the year since 1945. Next is 10° in 1986.
Au Sable’s center stands about 870 ft above sea level. Within three miles the land runs from 360 ft to 1,130 ft, a difference of 770 ft: hilly country. The highest named summit within 15 miles is Jay Mountains, about 3,600 ft, 15 miles south-southwest.
Under the town center the state geologic map shows Metanorthosite and anorthositic gneiss (gneiss, metaanorthosite), from the Mesoproterozoic, 1 to 1.6 billion 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.
Gneiss. Age: Mesoproterozoic, 1 to 1.6 billion years old. About 6 mi of the line.
Gneiss, metaanorthosite. Age: Mesoproterozoic, 1 to 1.6 billion years old. About 4 mi of the line.
Unconsolidated. Age: Quaternary, less than 2.6 million years old. About 3 mi of the line.
Metasedimentary, migmatite. Age: Mesoproterozoic, 1 to 1.6 billion years old. About 3 mi of the line.
Dolostone. Age: Cambrian to Early Ordovician, 471 to 542 million years old. About 2 mi of the line.
Sandstone. Age: Cambrian, 487 to 497 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. 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 Au Sable reaches the St. Lawrence River by way of the Ausable and the Richelieu: about 130 river miles. The St. Lawrence carries it on to the Atlantic.
Lake on the way: Lake Champlain.
80 miles of the trip are on the Richelieu.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Au Sable; river miles along the main stem, rounded.
Au Sable has a warm-summer humid continental climate. Summer afternoons average 81° in July; winter nights fall to about 10° in January. About 31 inches of rain fall in a normal year.
On November 14 Au Sable normally reaches 46° and falls to 29°. The record high is 64°, in 1959; the record low 11°, in 2019. The most rain on this date, 0.88 in, fell in 2009.
Normals 1991–2020 and records since 1945 from the Plattsburgh Area threaded record (Plattsburgh International Airport, 10 miles north-northeast, 700 ft lower). NOAA, through RCC-ACIS.
