View source for Glacial Lake Missoula

{{short description|Prehistoric proglacial lake in Western Montana}}
{{Use American English|date=July 2025}}
{{Use mdy dates|date=June 2023}}
{{Infobox protected area
| name          = Lake Missoula
| photo         = 
| photo_alt     = 
| photo_caption = 
| photo_width   = 
| map           = USA Montana
| map_alt       = 
| map_caption   = Map of [[Montana]]
| map_width     = 
| location      = Western [[Montana]]
| nearest_city  = 
| coordinates   = {{coord|46|56|20|N|114|08|37|W|region:US-MT|format=dms|display=inline,title}}
| coords_ref    = 
| area_km2      = 7770
| embedded      = {{designation list | embed = yes
  | designation1 = NNL
  | designation1_date = 1966
  }}
}}
{{Infobox body of water
| name               = Lake Missoula
| image              = Orillas fósiles del lago Missoula.jpg
| caption            = Wave-cut strandlines cut into the slope at left in photo. These cuts record former high-water lines, or shorelines. Gullies above the highway are the result of modern-day erosion. ([[National Park Service|NPS]] Photo)
| image_bathymetry   = 
| pushpin_map        = Montana
| caption_bathymetry = 
| coords             = {{coord|46|56|20|N|114|08|37|W|region:US-MT|format=dms}}
| location           = North America{{where|date=October 2025}}
| group              = 
| lake_type          = [[:Category:Former lakes|former lake]]
| inflow             = [[Channeled Scablands]]
| outflow            = [[Wallula Gap]] of the [[Columbia River]]
| catchment          = 
| basin_countries    = United States
| length             = {{convert|200|mi|km|abbr=on}}
| width              = {{convert|57|mi|km|abbr=on}}
| area               = {{convert|7700|km2|sqmi|0|abbr=on}}
| depth              = 
| max-depth          = {{convert|2000|ft|m|0|abbr=on}}
| volume             = {{convert|2100|km3|cumi|abbr=on}}
| residence_time     = N/A due to multiple historic fill / drain events
| shore              = 
| elevation          = {{convert|4206|ft|m|0|abbr=on}}
| islands            = 
| islands_category   = 
| cities             = 
| reference          = {{cite book | last =Bjornstad | first =Bruce N. | title =On the trail of the Ice Age floods : a geological field guide to the mid-Columbia basin / Bruce Bjornstad. | publisher =Keokee Books | date =c. 2006 | location =Sandpoint, Idaho | pages =4  | isbn = 978-1-879628-27-4}}
}}

[[Image:GLMsed.jpg|thumb|Sediment deposited by the lake with a hammer for scale.]]
'''Lake Missoula''' was a prehistoric [[proglacial lake]] in western [[Montana]] that existed periodically at the end of the last [[ice age]] between 15,000 and 13,000 years ago. The lake measured about {{Convert|7770|km2|sqmi|-1}} and contained about {{convert|2100|km3}} of water, half the volume of [[Lake Michigan]].<ref>{{cite book | last =Bjornstad | first =Bruce N. | title =On the trail of the Ice Age floods : a geological field guide to the mid-Columbia basin / Bruce Bjornstad. | publisher =Keokee Books | date =c. 2006 | location =Sandpoint, Idaho | pages =4  | isbn = 978-1-879628-27-4}}</ref>

The ''Glacial Lake Missoula National Natural Landmark'' is located about 110 kilometers  (68&nbsp;mi) northwest of [[Missoula, Montana]], at the north end of the Camas Prairie Valley, just east of Montana Highway 382 and Macfarlane Ranch. It was designated as a [[National Natural Landmark]] in 1966 because it contains the great ripples (often measuring {{Convert|25|to|50|ft|m}} high and {{Convert|300|ft}} long) that served as a strong supporting element for [[J Harlen Bretz]]'s contention that [[Washington (state)|Washington]] State's [[Channeled Scablands]] were formed by repeated cataclysmic floods over only about 2,000 years, rather than through the millions of years of erosion that had been previously assumed.<ref>{{cite book | last =Soennichsen | first =John | title =Bretz's Flood : The Remarkable Story of a Rebel Geologist and the World's Greatest Flood / John Soennichsen. | publisher =Sasquatch Books | date =c. 2008 | location =Seattle, Washington | pages =215–248  | isbn = 978-1-57061-631-0}}</ref><ref>{{Cite web
|url=https://www.nps.gov/subjects/nnlandmarks/site.htm?Site=GLLA-MT
|title=National Natural Landmarks - National Natural Landmarks (U.S. National Park Service)
|website=www.nps.gov|language=en
|quote="Year designated: 1966"
|access-date=2019-03-22}}</ref>

The lake was the result of an [[proglacial lake|ice dam]] on the [[Clark Fork (river)|Clark Fork]] caused by the southern encroachment of a finger of the [[Cordilleran ice sheet]] into the [[Idaho Panhandle]] (at the present-day location of [[Clark Fork, Idaho]], at the east end of [[Lake Pend Oreille]]). The height of the ice dam typically approached {{convert|610|m}}, flooding the valleys of western Montana approximately {{convert|320|km}} eastward.  It was the largest ice-dammed lake known to have occurred.<ref name = "Alt">{{cite book | first = David | last = Alt | title = Glacial Lake Missoula and Its Humongous Floods / David Alt | publisher = Mountain Press | location =Missoula, Montana | pages =27–28 | date = c. 2001| isbn = 0-87842-415-6}}</ref>

The periodic rupturing of the ice dam resulted in the [[Missoula Floods]] &ndash; cataclysmic [[flood]]s that swept across [[eastern Washington]] and down the [[Columbia River Gorge]] approximately 40 times during a 2,000 year period. The cumulative effect of the floods was to excavate {{convert|210|km3}} of [[loess]], sediment and basalt from the [[channeled scablands]] of eastern Washington and to transport it downstream.<ref name = "Allen">{{cite book | last =Allen | first =John Eliot |author2=Burns, Marjorie |author3=Sargent, Sam C. | title =Cataclysms on the Columbia : a layman's guide to the features produced by the catastrophic Bretz floods in the Pacific Northwest | publisher =Timber Press | date =c. 1986 | location =Portland, OR | pages =104 | isbn =0-88192-067-3}}</ref> These floods are noteworthy for producing [[canyon]]s and other large [[geologic]] features through [[Catastrophism|cataclysms]] rather than through more typical [[Uniformitarianism|gradual processes]].

In addition, [[Middle Pleistocene|Middle]] and [[Early Pleistocene]] Missoula flood deposits have been documented to comprise parts of  the [[glaciofluvial deposits]], informally known as the ''Hanford formation'' that are found in parts of the Othello Channels, Columbia River Gorge, [[Channeled Scabland]], Quincy Basin, Pasco Basin, and the [[Walla Walla Valley]]. The age of these deposits is demonstrated by the presence of multiple [[interglacial]] [[calcrete]]s interbedded in these glaciofluvial deposits, sequences of sediments with normal and reverse [[magnetostratigraphy]], [[optically stimulated luminescence]] dating, and [[unconformity]] truncated [[clastic dike]]s. Based upon these criteria, Quaternary geologists estimated that the oldest of the [[Pleistocene]] Missoula floods happened before 1.5 million years ago. The older Pleistocene glaciofluvial deposits within the Hanford formation are fragmentary in nature because they have been repeatedly eroded and largely removed by subsequent Missoula floods. Because of the fragmentary nature of older glaciofluvial deposits, the exact number of older Missoula floods, which are known as ''Ancient Cataclysmic Floods'', that occurred during the Pleistocene cannot be estimated with any confidence. Although Lake Missoula likely was the source of many of the Ancient Cataclysmic Floods, the fragmentary nature of the older deposits within the Hanford formation makes precise determination of the precise origin of the floods that deposited them very difficult.<ref name="Medley2012a">Medley, E. (2012) ''Ancient Cataclysmic Floods in the Pacific Northwest: Ancestors to the Missoula Floods.'' Unpublished Masters thesis, Portland State University, Portland, Oregon. 174 pp.</ref><ref name="Spencerothers2012a">Spencer, P. K., and M. A. Jaffee (2002) ''Pre-Late Wisconsinan Glacial Outburst Floods in Southeastern Washington—The Indirect Record.'' Washington Geology. vol. 30, no. 1/2, pp. 9–16.</ref>

==Geology==
===Ice dam on the Clark Fork River===
The [[Cordilleran ice sheet]] originating in [[British Columbia]] expanded out of the mountains and southward.  A tongue of ice pushed down the Purcell Valley or [[Purcell Trench]], reaching south beyond [[Lake Pend Oreille]].  This Purcell Lobe blocked the natural outlet of the [[Clark Fork River]]. Including its tributaries, Clark Fork represented western Montana's most important river system. The ice mass that effectively dammed Clark Fork was about {{convert|2000|ft|m}} deep and extended for at least 10 miles; some say it extended as much as 30 miles.<ref name=Floods>Glacial Lake Missoula; The glacial lake, at its maximum height and extent, may have contained 500 – 600 cubic miles of water; 9/18/2019;  hugefloods.com/LakeMissoula.html</ref> The ice dam reached east up the Clark's Fork to Cabinet, Montana, and southward around the mountain to [[Bayview, Idaho]] on the south tip of Lake Pend Oreille in [[Farragut State Park]].  Here, the ice sheet stood over {{convert|2000|ft|m}} and {{convert|25|mi|km}} south of Lake Missoula.<ref name=Deluge>Our Cataclysmic Floodscape, A Guide to the Incredible Ice Age Floods in Northern Idaho; Ice Age Flood Institute, Oregon-Washington-Idaho-Montana;  IAFI.org</ref>

===Lake levels===
The Clark Fork's drainage is a network of valleys among high mountain ranges. Lake Missoula formed through this region of western [[Montana]].  It is named for the city of [[Missoula, Montana|Missoula]] in the upper reaches of the Clark Fork watershed. The mountains surrounding the city show the [[strandlines]] from the lake nearly 20,000 years ago.<ref name=Floods/> At its largest extent, Lake Missoula's depth exceeded {{convert|2000|ft|m}} and may have held {{convert|600|cumi|km3|abbr=on}} of water, as much as Lake Erie and Lake Ontario combined. The surface area covered {{convert|3,000|sqmi|km2|0|abbr=on}} and the shoreline attained an elevation of {{convert|4200|ft|m}}.

The lake spread through the [[Clark Fork River]] basin, reaching east of Missoula, {{convert|259|mi|km}} to [[Gold Creek (Montana)|Gold Creek]]; northeast up the [[Blackfoot River (Montana)|Blackfoot River]] {{convert|270|mi|km}} to Lake Alva; {{convert|253|mi|km}} and east of [[Ovando, Montana|Ovando]] {{convert|270|mi|km}}.  Two large lobes formed to the south and north.  To the south the Bitterroot Valley filled as far as [[Sula, Montana]], {{convert|286|mi|km}}.  To the north the [[Flathead River]] basin became an expansive body of water, creating an island of [[Red Sleep Mountain]] (in the [[CSKT Bison Range]]) and extending north {{convert|286|mi|km}} to [[Polson, Montana|Polson]] at the basin of the Flathead Ice Lobe and {{convert|286|mi|km}} up the [[Little Bitterroot River]] to Niarada some {{convert|132|mi|km}} above the Flathead Rivers mouth at the Clarks Fork.<ref name=Floods/>

The water was deep (average – {{convert|800|ft|m|disp=or}}): maximum – {{convert|2100|ft|m|disp=or}}), dark and murky with sediment. Fish fossils have not been found in deposits of Lake Missoula. Possibly, glacial sediment, [[rock flour]], suspended in the turbid lake water which created an hostile aquatic habitat for fish. In addition, fossils of large mammals ([[megafauna]]), i.e.; [[mammoths]], [[mastodons]] and [[bison]] which may have roamed nearby, not been found. Similarly, neither the remains or artifacts of contemporaneous humans have been found associated with Lake Missoula.<ref name=Floods/> The Clark Fork River flows into Lake Pend Oreille at {{convert|2062|ft|m}}.<ref name=Floods/>

==Basins of Lake Missoula==
{|class="wikitable" style="text-align: center; width: 800px; height: 200px;"
|- Wikitable
|+ '''Reaches of Glacial Lake Missoula'''
|-
! Reach<ref name=Floods/>
! Riverway<ref name=Floods/>
!| Length
! Max depth<ref>My Elevation, RDH Software, Version 11.52; 2014–2019 by RDH Software</ref>
! Outlet<ref name=Floods/>
!| Features
|-
| Clark Fork Canyon
| [[Clark Fork River]]
| {{convert|92|mi|km}} from the ice dam at [[Lake Pend Oreille]] to Ninemile
| {{convert|2150|ft|m}}
| Blocked at [[Lake Pend Orielle]] in Idaho
| Eddy Narrows, St. Regis Notch, Ninemile Rhythmites
|-
| Flathead River Basin
| [[Flathead River]]
| {{convert|71|mi|km}} from the Clark Fork at [[Paradise, Montana|Paradise]] to [[Polson, Montana|Polson]], where the glacier stood
| {{convert|1665|ft|m}} at [[Perma, Montana|Perma]]
| Joins the Clark Fork River at Paradise
| [[Pingo|Ninepipes Pingo Scars]], Paradise Center, [[CSKT Bison Range]], Sloan Bridge Sediments
|-
| Little Bitterroot Valley
| [[Little Bitterroot River]]
| {{convert|43|mi|km}} from the Flathead River to the glacial front near [[Niarada, Montana|Niarada]]
| {{convert|1363|ft|m}} at [[Camas Prairie]]
| Joins the Clark Fork River near [[Ninepipe National Wildlife Refuge]] at Sloan Bridge and crossed the divide between the Clark Fork and the Little Bitterroot Rivers at Rainbow Lake
| Gulch Fill, Rainbow "Dog" Lake, [[Kolk (vortex)|Markle Pass Kolk]], Camas Prairie Ripples
|-
| Missoula Basin
| [[Clark Fork River]]
| {{convert|37|mi|km}} from Ninemile to [[Lolo, Montana|Lolo]]
| {{convert|1176|ft|m}} at Ninemile
| Enters the lower Clark Fork Canyon Reach at Ninemile
| [[Glacial erratic]] and [[Mount Jumbo|Strandlines]]
|-
| Bitterroot Valley
| [[Bitterroot River]]
| {{convert|68|mi|km}} from [[Lolo, Montana|Lolo]] in the Missoula Basin to near [[Sula, Montana|Sula]]
| {{convert|940|ft|m}} at Lolo
| Enters Missoula Basin at Lolo
| Features
|-
| Blackfoot River Valley
| [[Blackfoot River (Montana)|Blackfoot River]]
| {{convert|57|mi|km}} from [[Bonner, Montana|Bonner]] to [[Rainy Lake (Montana)|Rainy Lake]] on the [[Clearwater River (Montana)|Clearwater River]] and {{convert|73|mi|km}} up the Blackfoot River to near Helmsville
| {{convert|566|ft|m}} at [[Potomac, Montana|Potomac]]
| Joins the Clark Fork River
| Features
|-
| Upper Clark Fork 
| [[Clark Fork River]]
| {{convert|55|mi|km}} from the Bonner Flats to near [[Gold Creek, Montana|Gold Creek]] on Interstate 90
| {{convert|1197|ft|m}} at [[Bonner, Montana|Bonner]]
| Enters the Missoula Basin of the Clark Fork River west of Bonner
| Gold Creek High Water Monument
|}

===Clark Fork Canyon===
This reach follows Montana Route 200 up the [[Clark Fork River]] canyon, {{convert|92|mi|km}} to [[Paradise, Montana|Paradise]], then follows the Clark Fork, then {{convert|49|mi|km}} through the Paradise-St. Regis Canyon along [[Montana Highway 135]]. At [[St. Regis, Montana|St. Regis]], the canyon opens out and continues to the east {{convert|49|mi|km}} with the river paralleled by Interstate 90 to as far as Ninemile, where it opens out into the Missoula basin. A western branch of this basin runs up the [[St. Regis River (Montana)|St. Regis River]] another {{convert|32|mi|km}} along with Interstate 90 to near [[Riverbend, Montana|Riverbend]]. 
*[[Lookout Pass]], {{convert|4679|ft|m}} asl along Interstate 90
*[[Thompson Falls, Montana|Thompson Falls]] – Located in the northern or western reach of the basin, the modern river passes through a layer of harder rock, forming a cascade.
*: Nine Mile Rhythmites – Located at the eastern end of the basin, near Nine Mile. A light pink sand and silt deposited on the bottom of the lake. The silt deposits exist where the basin was wide, and when the lake drained, the area was not reached by the fast current of the water moving downstream. Each lay represents a period of still water behind the ice dam. The series reflects each period of still water with the intervening draining of the lake. As with "[[varve]]s", darker layers are winter deposits, comprising fine particles in quiet water, and the lighter layers are coarser particles from the more active summer currents. Here, the number of layers represent 1,000 years of sediment.<ref name=CataclysmicLake2019>A Guide to the Incredible Ice Age Floods "Where IT Began" – Glacial Lake Missoula, Our Cataclysmic Floodscape; Ice Age Flood Institute, Oregon – Washington – Idaho – Montana; IAFI.org; 9/25/2019</ref>

===Flathead Basin===
The Flathead basin abutted the south face of the ice sheet. For most of this period, the glacial ice reached south to [[Polson, Montana|Polson]], covering the entirety of [[Flathead Lake]]. The basin drains from the Polson Moraine at the south end of Flathead Lake, south to [[Ravalli, Montana|Ravalli]], with a major lobe up the Little Bitterroot River and a minor basin on Camas Creek near [[Perma, Montana|Perma]].  
* Little Money Creek Gulch Fill – Exit 96, north on US 93 to Ravalli. The coarse materials filled the side gulches on the narrow valley as Lake Missoula drained; eddy currents in tributary gulches deposited debris.<ref name=CataclysmicLake2019/>
* Rainbow "Dog" Lake – Drains into the Clark Fork near [[Plains, Montana|Plains]]. During the existence of Lake Missoula, it was a drain for the Little Bitterroot basin when the lake level exceeded {{convert|3620|ft|m}} asl and for the Camas Prairie basin when the lake level exceeded {{convert|3680|ft|m}} asl. At the maximum depth of Lake Missoula, the valley was a {{convert|520|ft|m|adj=mid|-deep}} waterway. Rainbow Lake is thought to be a cataract retreat lake, formed by a {{convert|100|ft|adj=on}} waterfall. The Clark Fork River dropped {{convert|1700|ft|m}} near Plains, creating a {{convert|60|to|70|mph|kph}} current through Boyer Creek. A weaker layer of rock beneath a more resistant layer was removed, causing the lip of the falls to retreat backward. Evidence is provided by the debris that lines the valley bottom.<ref name=CataclysmicLake2019/>
* [[Camas prairie|Camas Prairie]] [[Giant current ripples|Mega ripples]] – Camas Prairie is a small basin on Camas Creek, north of Perma. At the maximum water levels of the Hwy 382 through the prairie to information sign at mile marker13. Multiple long ridges of sediment, {{convert|25|ft}} height and {{Convert|100|ft|m}} apart. Average height between {{Convert|13|and|30|ft|m}}. Formed during the outflow of water during a break in the ice dam.<ref name=CataclysmicLake2019/> The Camas Prairie Basin filled when Lake Missoula reached {{convert|2770|ft|m}} asl. As the water in the Lake Missoula Basin rose, this basin gained a second outlet through Rainbow Lake at {{convert|3588|ft|m}} asl; Willis Gulch {{convert|3349|ft|m}} asl; Markle Pass {{convert|3352|ft|m}} asl; and Big Gulch {{convert|3435|ft|m}} asl.
* Markle Pass Kolks – Montana Highway 382 travels through Markle Pass between Camas Prairie and the Little Bitterroot Valley. The [[Kolk (vortex)|Kolks]] were carved out of the bedrock by strong underwater [[vortices]] created as Lake Missoula quickly drained during the great floods. When the tornado-like currents reached the bottom of the waterway, rocks were pulled out of the bottom surface. This debris can be found downstream towards Camas Prairie and Burgess Lake.<ref name=CataclysmicLake2019/>

===Missoula Basin===
The basin extends from [[Missoula]], west to Ninemile and up the Ninemile Creek valley. This  {{convert|39|mi|km|adj=mid|-long}} valley broadens from {{convert|5|mi|0}} at Ninemile to {{convert|10|mi|0}} at Missoula. The central part of this basin around Missoula is {{convert|8|mi|0}} wide east–west and {{convert|10|mi|0}} north-south. The basin is bordered by Rattlesnake Ridge on the north and Petty Mountain on the south(west). Features:  strandlines along the valleys east flank.  
* [[Glacial erratic]] on the grounds of the [[University of Montana]]<ref name=CataclysmicLake2019/>
* [[High water mark|Strandlines]] can be seen on the slopes of both [[Mount Jumbo]] ({{convert|4764|ft|m}} asl) and [[Mount Sentinel]] ({{convert|5081|ft|m}} asl), east in the Missoula Valley. These lines represent lake levels as the ice dam in the [[Purcell Trench]] failed and a lower lake level formed.<ref name=CataclysmicLake2019/>
* Nine Mile Rhythmites on the bottom of the lake are visible.

===Hamilton Basin===
The basin extends from south of [[Conner, Montana|Conner]] to [[Lolo, Montana|Lolo]], {{convert|57|mi|km}} to the north.  The [[Bitterroot Mountains]] form the west shore and the [[Sapphire Mountains]] the east.

===Blackfoot River Basin===
The valleys of [[Potomac, Montana|Potomac]], Greenough, and [[Ovando, Montana|Ovando]]-[[Helmville, Montana|Helmville]] are linked by the [[Blackfoot River (Montana)|Blackfoot River]] east of Missoula. A second reach, up the [[Clearwater River (Montana)|Clearwater River]], joins the Blackfoot River at Clearwater. This basin joins the Clark Fork at [[Bonner, Montana|Bonner]]. Upper valleys of the Clearwater-Blackfoot River basins run {{convert|394|mi|km}} from [[Seeley Lake, Montana|Seeley Lake]], eastward to Browns Lake along Montana Route 83 and Montana Route 200.

===Upper Clark Fork===
The Clark Fork of the Columbia River has its headwater near [[Butte, Montana|Butte]], {{convert|130|mi|km}} east of Missoula. Lake Missoula reached up the valley, about {{convert|55|mi|km}} to the east along I-90 to just east of [[Gold Creek, Montana|Gold Creek]]. Smaller reaches formed along the tributary valleys of Gold Creek, {{convert|13.5|mi|km}} up Flint Creek, forming an {{convert|8|mi|km|adj=mid|-wide|0}} basin, up Lower Willow Creek, and {{convert|20|mi|km}} up Rock Creek.

==See also==
[[File:Map missoula floods.gif|thumb|{{legend|#00CEFF|Cordilleran Ice Sheet}}
{{legend|#FFFF00|maximum extent of Glacial Lake Missoula (eastern) and Glacial Lake Columbia (western)}}
{{legend|#FFCE00|areas swept by Missoula and Columbia floods}}]]
* {{annotated link|Missoula floods}}
* {{annotated link|Glacial lake outburst flood}}
* {{annotated link|Giant current ripples}}
* {{annotated link|Ice Age Floods National Geologic Trail}}
* {{annotated link|List of prehistoric lakes}}

== References ==
{{reflist}}
{{Commons category|Glacial Lake Missoula}}

==External links==
*[https://volcanoes.usgs.gov/observatories/cvo/Historical/LewisClark/Maps/map_missoula_floods.shtml USGS Site on Glacial Lake Missoula]
*[https://www.nps.gov/subjects/nnlandmarks/site.htm?Site=GLLA-MT US Park Service Site for Glacial Lake Missoula National Natural Landmark]
*[[Public Broadcasting Service|PBS]]'s [[Nova (American TV program)|''NOVA'' (TV series)]]: [https://www.pbs.org/wgbh/nova/megaflood/ Mystery of the Megaflood] for information on the Missoula Floods
*[http://seattletimes.nwsource.com/html/pacificnw09302007/2003905120_pacificpice30.html The Seattle Times' ''Pacific NW'' magazine] – "Trailing an Apocalypse" – 30-Sep-2007
*[http://www.iafi.org The Ice Age Floods Institute]
*[https://web.archive.org/web/20110715051759/http://www.patiastephens.com/PDFs/montanan-sedimental-journey.pdf U of Montana publication, ''The Montanan'', "Sedimental Journey: Following the Path of Glacial Lake Missoula's Flood Waters."]

{{Ice Age Floods}}
{{Pleistocene Lakes and Seas}}
{{Missoula, Montana}}

{{authority control}}

{{DEFAULTSORT:Missoula, Lake}}
[[Category:Former lakes of the United States]]
[[Category:Geology of Montana]]
[[Category:Geology of Idaho]]
[[Category:Natural history of Montana]]
[[Category:Natural history of Idaho]]
[[Category:National Natural Landmarks in Montana]]
[[Category:Proglacial lakes]]
[[Category:History of Missoula, Montana]]