The Grand Isle 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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66° on Nov. 11, 2020, the hottest reading for this week of the year since 1996. Next is 63° in 2002.
Grand Isle’s center stands about 550 ft above sea level. Within three miles the land runs from 430 ft to 950 ft, a difference of 520 ft: hilly country. The highest named summit within 15 miles is Cyr Mountain, about 1,190 ft, 6 miles west.
Under the town center the state geologic map shows Devonian - Silurian unnamed sedimentary rocks (sandstone, mudstone), from the Silurian to Devonian, 359 to 445 million years old.
The section below crosses 5 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 22×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Mudstone, sandstone. Age: Ordovician, 445 to 487 million years old. About 6 mi of the line.
Sandstone, mudstone. Age: Silurian to Devonian, 359 to 445 million years old. About 3 mi of the line.
Mudstone, sandstone. Age: Silurian, 422 to 445 million years old. About 3 mi of the line.
Mudstone. Age: Silurian, 422 to 445 million years old. About 1 mi of the line.
Sandstone, conglomerate. Age: Silurian, 422 to 445 million years old. About 0.7 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 Grand Isle reaches the Bay of Fundy and the Atlantic Ocean by way of the Saint John: about 240 river miles.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Grand Isle; river miles along the main stem, rounded.
Grand Isle has a warm-summer humid continental climate. Summer afternoons average 76° in July; winter nights fall to about 3° in January. About 33 inches of rain fall in a normal year.
On November 14 Grand Isle normally reaches 39° and falls to 26°. The record high is 54°, in 2006; the record low 5°, in 2019. The most rain on this date, 1.49 in, fell in 2006.
Normals 1991–2020 and records since 1996 at Frenchville Northern Aroostook Airport, 7 miles west-southwest, 440 ft higher. NOAA, through RCC-ACIS.
