Editing Great Falls, Montana (section)

== Geography ==
[[File:Glacial lakes in Montana.jpg|thumb|upright=1.3|Map of Montana showing Glacial Lake Great Falls]]
Great Falls is located near [[Great Falls (Missouri River)|several waterfalls]] on the [[Missouri River]]. It lies near the center of [[Montana]] on the northern [[Great Plains]]. It lies next to the [[Rocky Mountain Front]] and is approximately {{convert|100|mi|km}} south of the Canada–US border.{{Citation needed|date=February 2019}} According to the [[United States Census Bureau]], the city has a total area of {{convert|22.26|sqmi|sqkm|2}}, of which {{convert|21.79|sqmi|sqkm|2}} is land and {{convert|0.47|sqmi|sqkm|2}} is water.<ref name="Gazetteer files">{{cite web|url=https://www.census.gov/geo/www/gazetteer/files/Gaz_places_national.txt|title=US Gazetteer files 2010|publisher=[[United States Census Bureau]]|archive-url=https://web.archive.org/web/20120112090031/http://www.census.gov/geo/www/gazetteer/files/Gaz_places_national.txt|archive-date=January 12, 2012|url-status=dead|access-date=2012-12-18}}</ref>

=== Geology ===
The city of Great Falls lies atop the [[Great Falls Tectonic Zone]], an intracontinental [[Shear (geology)|shear zone]] between two [[geologic province]]s of [[Basement (geology)|basement rock]] of the [[Archean]] period which form part of the North American [[continent]].<ref>Boerner, D.E.; Craven, J.A.; Kurtz, R.D.; Ross, G.M.; and Jones, F.W. "The Great Falls Tectonic Zone: Suture or Intracontinental Shear Zone?" ''[[Canadian Journal of Earth Sciences]].'' 35:2 (1998); O'Neill, J. Michael and Lo, David A. "Character and Regional Significance of Great Falls Tectonic Zone, East-Central Idaho and West-Central Montana". ''AAPG Bulletin.'' 69 (1985); Mueller, Paul A.; Heatherington, Ann L.; Kelly, Dawn M.; Wooden, Joseph L.; and Mogk, David W. "Paleoproterozoic Crust Within the Great Falls Tectonic Zone: Implications for the Assembly of Southern Laurentia". ''Geology.'' 30:2 (February 2002); Harms, Tekla A.; Brady, John B.; Burger, H. Robert; and Cheney, John T. ‘Advances in the Geology of the Tobacco Root Mountains, Montana, and Their Implications for the History of the Northern Wyoming Province.’ ''Precambrian geology of the Tobacco Root Mountains, Montana.'' Special Papers, Volume 377. John B. Brady, H. Robert Burger, John T. Cheney, and Tekla A. Harms, eds. Boulder, Colo.: Geological Society of America, 2004. {{ISBN|0-8137-2377-9}}</ref> The city lies at the southern reach of the [[Laurentide Ice Sheet]], a vast glacial sheet of ice which covered much of North America during the [[last glacial period]]. Approximately 1.5&nbsp;million years ago, the Missouri River flowed northward into a [[Endorheic basin|terminal lake]].<ref name="Clawson">Clawson, Roger and Shandera, Katherine A. ''Billings: The City and the People.'' Helena, Mont.: Farcountry Press, 1998. {{ISBN|1-56037-037-8}}</ref><ref>McRae, W.C. and Jewell, Judy. ''Moon Montana.'' 7th ed. Cambridge, Massachusetts: PublicAffairs, 2009. {{ISBN|1-59880-014-0}}</ref> The Laurentide Ice Sheet pushed the river southward.<ref name="Clawson" /><ref name="Montagne">Montagne J.L. 'Quaternary System, Wisconsin Glaciation.' ''Geologic Atlas of the Rocky Mountain Region.'' Denver: Rocky Mountain Association of Geologists, 1972.</ref> Between 15,000 [[Common Era|BCE]] and 11,000 BCE, the Laurentide Ice Sheet blocked the Missouri River and created [[Glacial Lake Great Falls]].<ref name="Feathers">[http://gsa.confex.com/gsa/inqu/finalprogram/abstract_53968.htm Feathers, James K. and Hill, Christopher L. "Luminescence Dating of Glacial Lake Great Falls, Montana, U.S.A."] {{Webarchive|url=https://web.archive.org/web/20141129125733/https://gsa.confex.com/gsa/inqu/finalprogram/abstract_53968.htm |date=November 29, 2014 }} ''XVI International Quaternary Association Congress.'' Stratigraphy and Geochronology Session. International Quaternary Association, Reno, 2003.</ref><ref name="Montagne" /><ref>Hill, Christopher L. and Valppu, Seppo H. "Geomorphic Relationships and Paleoenvironmental Context of Glaciers, Fluvial Deposits, and Glacial Lake Great Falls, Montana". ''Current Research in the Pleistocene.'' 14 (1997); Hill, Christopher L. "Pleistocene Lakes Along the Southwest Margin of the Laurentide Ice Sheet". ''Current Research in the Pleistocene.'' 17 (2000); Hill, Christopher L. and Feathers, James K. "Glacial Lake Great Falls and the Late-Wisconsin-Episode Laurentide Ice Margin". ''Current Research in the Pleistocene.'' 19 (2002); [http://pubs.usgs.gov/sim/2005/2860/ Reynolds, Mitchell W. and Brandt, Theodore R. ''Geologic Map of the Canyon Ferry Dam 30' x 60' Quadrangle, West-Central Montana: U.S. Geological Survey Scientific Investigations Map 2860, scale 1:100,000.''] Scientific Investigations Map 2860. Washington, D.C.: U.S. Geologic Survey, 2005.</ref> About 13,000 BCE, as the glacier retreated, Glacial Lake Great Falls emptied catastrophically in a [[glacial lake outburst flood]].<ref name="Feathers" /> The current course of the Missouri River essentially marks the southern boundary of the Laurentide Ice Sheet.<ref>"Agriculture". In ''Encyclopedia of the Great Plains.'' David J. Wishart, ed. Lincoln, Neb.: University of Nebraska Press, 2004. {{ISBN|0-8032-4787-7}}</ref> The Missouri River flowed eastward around the glacial mass, settling into its present course.<ref name="Clawson" /> As the ice retreated, meltwater from Glacial Lake Great Falls poured through the [[Highwood Mountains]] and eroded the mile-long, {{convert|500|ft|m|adj=mid|-deep}} [[Shonkin Sag]], one of the most famous prehistoric meltwater channels in the world.<ref>Axline, Jon and Bradshaw, Glenda Clay. ''Montana's Historical Highway Markers.'' Rev. ed. Helena, Mont.: Montana Historical Society, 2008. {{ISBN|0-9759196-4-4}}; Bowman, Isaiah. "Forest Physiography: Physiography of the United States and Principles of Soils in Relation to Forestry". ''American Environmental Studies.'' Reprint ed. Charles Gregg, ed. New York: Arno Press, 1970. {{ISBN|0-405-02659-5}}</ref>

===Climate===
Great Falls has a [[Semi-arid climate#Cold semi-arid climates|cold semi-arid climate]] ([[Köppen climate classification|Köppen]]: ''BSk''),<ref>{{Cite web|url=http://www.weatherbase.com/weather/weather-summary.php3?s=57727&cityname=Great+Falls,+Montana,+United+States+of+America|title=Great Falls, Montana Köppen Climate Classification (Weatherbase)|website=Weatherbase|access-date=2019-02-09}}</ref> with a notable amount of summer precipitation occurring in the form of thunderstorms. Winters are very cold, long and often snowy, though periods of [[chinook wind]]s do cause warm spells and raise the maximum temperature above {{convert|50|F|C|disp=or}} on an average of fifteen afternoons during the three-month winter period.<ref>[[National Weather Service|NOW]]; [https://w2.weather.gov/climate/xmacis.php?wfo=tfx NOAA Online Weather Data], Great Falls, Montana</ref> In the absence of such winds, shallow cold snaps are common; there is an average of 20.8 nights with a low of {{convert|0|°F|1}} or colder and 44 days failing to top freezing. The wettest part of the year is the spring. Summers are hot and dry, with highs reaching {{convert|90|°F|1}} on nineteen days per year, though the [[diurnal temperature variation]] is large and easily exceeds {{convert|30|F-change|1}}.<ref name= NCDC>{{cite web
| url = http://www.weather.com/outlook/travel/businesstraveler/wxclimatology/monthly/USMT0146
| title = Climatography of the United States No. 20 1971–2000: GREAT FALLS INTL AP, MT
| format = PDF
| access-date = 2011-01-26
| publisher = [[National Oceanic and Atmospheric Administration]]
}}</ref> Freak early and late summer snowfalls such as a two-day total of {{convert|8.3|in|m|abbr=on}} in August 1992 can occur, although the median snowfall from June to September is zero and on average the window for accumulating ({{convert|0.1|in|cm|abbr=on|disp=or}}) snowfall is October 2–May 13.<ref name = NCDC /> The average first and last freeze dates are September 21 and May 21, respectively, allowing a growing season of 122 days, although, excepting for July, a freeze has occurred in every month of the year. Extreme temperatures range from {{convert|−49|°F|1}} on February 15, 1936, to {{convert|107|°F|1}} on July 25, 1933.

{{Weather box
|location = Great Falls, Montana ([[Great Falls International Airport|Great Falls Int'l]]), 1991–2020 normals,{{efn|Mean monthly maxima and minima (i.e. the expected highest and lowest temperature readings at any point during the year or given month) calculated based on data at said location from 1991 to 2020.}} extremes 1891–present
|single line = Y
|Jan record high F = 67
|Feb record high F = 70
|Mar record high F = 78
|Apr record high F = 89
|May record high F = 100
|Jun record high F = 102
|Jul record high F = 107
|Aug record high F = 106
|Sep record high F = 102
|Oct record high F = 91
|Nov record high F = 76
|Dec record high F = 69

|Jan avg record high F = 57.1
|Feb avg record high F = 57.8
|Mar avg record high F = 66.7
|Apr avg record high F = 75.4
|May avg record high F = 82.7
|Jun avg record high F = 89.5
|Jul avg record high F = 97.1
|Aug avg record high F = 97.1
|Sep avg record high F = 90.8
|Oct avg record high F = 79.4
|Nov avg record high F = 64.9
|Dec avg record high F = 55.4
|year avg record high F = 98.8

|Jan high F = 35.3
|Feb high F = 37.1
|Mar high F = 46.1
|Apr high F = 54.9
|May high F = 64.6
|Jun high F = 72.8
|Jul high F = 84.3
|Aug high F = 83.2
|Sep high F = 71.7
|Oct high F = 57.0
|Nov high F = 43.7
|Dec high F = 35.6
|year high F = 57.2

|Jan mean F = 25.2
|Feb mean F = 26.2
|Mar mean F = 34.1
|Apr mean F = 42.4
|May mean F = 51.5
|Jun mean F = 59.4
|Jul mean F = 67.9
|Aug mean F = 66.7
|Sep mean F = 57.2
|Oct mean F = 44.8
|Nov mean F = 33.6
|Dec mean F = 26.0
|year mean F =

|Jan low F = 15.0
|Feb low F = 15.4
|Mar low F = 22.1
|Apr low F = 29.9
|May low F = 38.4
|Jun low F = 45.9
|Jul low F = 51.4
|Aug low F = 50.3
|Sep low F = 42.8
|Oct low F = 32.6
|Nov low F = 23.6
|Dec low F = 16.3
|year low F = 32.0

|Jan avg record low F = -15.2
|Feb avg record low F = -9.0
|Mar avg record low F = -1.9
|Apr avg record low F = 13.9
|May avg record low F = 25.8
|Jun avg record low F = 35.9
|Jul avg record low F = 41.9
|Aug avg record low F = 40.1
|Sep avg record low F = 29.3
|Oct avg record low F = 13.5
|Nov avg record low F = -2.7
|Dec avg record low F = -10.8
|year avg record low F = -24.6

|Jan record low F = −44
|Feb record low F = −49
|Mar record low F = −32
|Apr record low F = −10
|May record low F = 12
|Jun record low F = 31
|Jul record low F = 35
|Aug record low F = 30
|Sep record low F = 10
|Oct record low F = −11
|Nov record low F = −25
|Dec record low F = −43

|precipitation colour = green
|Jan precipitation inch = 0.55
|Feb precipitation inch = 0.59
|Mar precipitation inch = 0.68
|Apr precipitation inch = 1.73
|May precipitation inch = 2.43
|Jun precipitation inch = 2.72
|Jul precipitation inch = 1.23
|Aug precipitation inch = 1.22
|Sep precipitation inch = 1.33
|Oct precipitation inch = 1.07
|Nov precipitation inch = 0.68
|Dec precipitation inch = 0.53

|Jul snow inch = 0.0
|Aug snow inch = 0.3
|Sep snow inch = 0.8
|Oct snow inch = 5.2
|Nov snow inch = 9.2
|Dec snow inch = 9.6
|Jan snow inch = 9.2
|Feb snow inch = 10.1
|Mar snow inch = 10.1
|Apr snow inch = 9.4
|May snow inch = 1.9
|Jun snow inch = 0.3

|unit precipitation days = 0.01 in
|Jan precipitation days = 6.9
|Feb precipitation days = 8.2
|Mar precipitation days = 8.1
|Apr precipitation days = 10.0
|May precipitation days = 11.3
|Jun precipitation days = 11.8
|Jul precipitation days = 7.1
|Aug precipitation days = 6.8
|Sep precipitation days = 7.1
|Oct precipitation days = 7.4
|Nov precipitation days = 6.5
|Dec precipitation days = 6.5

|unit snow days = 0.1 in
|Jan snow days = 7.4
|Feb snow days = 8.1
|Mar snow days = 6.8
|Apr snow days = 4.6
|May snow days = 1.4
|Jun snow days = 0.2
|Jul snow days = 0.0
|Aug snow days = 0.1
|Sep snow days = 0.2
|Oct snow days = 3.3
|Nov snow days = 6.1
|Dec snow days = 7.1

|Jan sun = 125.1
|Feb sun = 151.7
|Mar sun = 237.5
|Apr sun = 245.7
|May sun = 286.6
|Jun sun = 316.5
|Jul sun = 377.4
|Aug sun = 330.8
|Sep sun = 254.4
|Oct sun = 200.4
|Nov sun = 124.8
|Dec sun = 105.4
|source 1 = NOAA (sun 1961–1990)<ref name= NOAA>{{cite web |url = https://w2.weather.gov/climate/xmacis.php?wfo=tfx |title = NowData – NOAA Online Weather Data |publisher = [[National Oceanic and Atmospheric Administration]] |access-date = 2021-05-04}}</ref>
|source 2 = NOAA<ref name=NCEI>
{{cite web
|url = https://www.ncei.noaa.gov/access/services/data/v1?dataset=normals-monthly-1991-2020&stations=USW00024143&format=pdf&dataTypes=MLY-TMAX-NORMAL,MLY-TMIN-NORMAL,MLY-TAVG-NORMAL,MLY-PRCP-NORMAL,MLY-SNOW-NORMAL
|publisher = National Oceanic and Atmospheric Administration
|title = U.S. Climate Normals Quick Access
|access-date = August 19, 2022
}}
</ref>

}}

=== Suburbs ===
[[Census-designated place]]s contiguous to the City of Great Falls include:
*[[Black Eagle, Montana|Black Eagle]]
*[[Malmstrom Air Force Base|Malmstrom AFB]]

===Nearby communities===
The entirety of Cascade County forms the Great Falls [[Metropolitan statistical area]].  Great Falls is an economic hub for a substantially larger region that includes most of north-central Montana. Small towns and census-designated places in Cascade County near Great Falls include:
{{div col|colwidth=20em}}
*[[Belt, Montana|Belt]]
*[[Cascade, Montana|Cascade]]
*[[Fort Shaw, Montana|Fort Shaw]]
*[[Gibson Flats, Montana|Gibson Flats]]
*[[Monarch, Montana|Monarch]]
*[[Neihart, Montana|Neihart]]
*[[Sand Coulee, Montana|Sand Coulee]]
*[[Simms, Montana|Simms]]
*[[Sun Prairie, Montana|Sun Prairie]]
*[[Sun River, Montana|Sun River]]
*[[Ulm, Montana|Ulm]]
*[[Vaughn, Montana|Vaughn]]
{{div col end}}