The Helena Flats 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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69° on Nov. 12, 1999, the hottest reading for this week of the year since 1899. Next is 64° in 1990.
Helena Flats’s center stands about 2,950 ft above sea level. Within three miles the land runs from 2,920 ft to 3,070 ft, a difference of 150 ft: gently rolling country. The highest named summit within 15 miles is Doris Mountain, about 7,380 ft, 8 miles east-northeast.
Under the town center the state geologic map shows Alluvium (gravel, sand, silt), from the Pleistocene to Holocene, less than 1.8 million years old.
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 5×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Silt, sand, clay. Age: Pleistocene to Holocene, less than 1.8 million years old. About 8 mi of the line.
Quartzite, metasiltstone, argillite. Age: Mesoproterozoic, 1 to 1.6 billion years old. About 7 mi of the line.
Age: Pleistocene to Holocene, less than 1.8 million years old. About 3 mi of the line.
Unconsolidated. Age: Pleistocene to Holocene, less than 1.8 million years old. About 3 mi of the line.
Gravel, sand, silt. Age: Pleistocene to Holocene, less than 1.8 million years old. About 2 mi of the line.
Quartzite, argillite, metasiltstone. Age: Mesoproterozoic, 1 to 1.6 billion 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.
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 Helena Flats reaches the Pacific Ocean by way of Gooderich Bayou, the Flathead, the Clark Fork, the Pend Oreille and the Columbia: about 1,090 river miles.
Lakes on the way: Flathead Lake, Lake Pend Oreille, Lake Umatilla and Noxon Rapids Reservoir.
460 miles of the trip are on the Columbia.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Helena Flats; river miles along the main stem, rounded.
Helena Flats has a warm-summer humid continental climate. Summer afternoons average 82° in July; winter nights fall to about 16° in January. A normal year brings about 54 inches of snow; with the rain, that comes to about 17 inches of water.
On November 14 Helena Flats normally reaches 40° and falls to 24°. The record high is 63°, in 1999; the record low −3°, in 2014. The most rain on this date, 1.40 in, fell in 1903.
Normals 1991–2020 and records since 1899 from the Kalispell Area threaded record (Kalispell Glacier Airport, 2 miles northwest). NOAA, through RCC-ACIS.
