Glacial Lake Missoula Questions

Nick stops in Missoula to ask questions about Ice Age lake shorelines above the University of Montana. Filmed on September 5, 2021.
Nick's 2015 video on Glacial Lake Missoula: • Glacial Lake Missoula
Nick's 2021 video with Brian Atwater at Steamboat Rock: • Brian Atwater at Steam...

[@Derecles260]

Professor Zentner, I was in your Geology of National Parks class, Winter Quarter of 2009. I want to thank you for being an amazing professor, who shared your passion with us which rubbed off greatly on at least myself. I initially registered for the class because it was a gen Ed requirement, little did I know it would be one of my favorite classes in all of my college career at CWU. As an adult about a year ago, I discovered your KZbin channel and am SO glad I did. Thank you for continuing to share your knowledge with not just your students, but the entire world. You are appreciated. Sincerely, An old student, Derek Price

[@caseyfield8239]

Nick, I am absolutely 100% interested in working on these shorelines and doing the work to flesh out more of these ice age mega floods. I am currently an undergrad in professional geology with a focus in hydrogeology attending Eastern Michigan University. I am intending to follow through and work through a masters and doctorate. These are the kinds of questions and thoughts that are what gets my mojo going. I would love to exchange emails and get some advice or start a dialogue about what are the most important goals to be working towards! Especially if I want to come work with you as a grad student. The world is a fascinating place! Love your work sharing these wonderful gems. can't wait for more of the cascade super team updates.

[@dcarder3336]

The shoreline notches were made seasonally while the water was filling the lake. During dry seasons the level would remain constant long enough for the wind lapping the waves, splashing water up onto the bank, washing away silt while exposing gravel and washing smaller gravel down, thus creating the notch-line. Then the rains and snowmelt raised the lake level a little higher and the process started over. The lines remained as the lake drained, no matter how many times it drained. The dates of the shoreline marks are random from top to bottom. That's what i think is possible...but I ain't no English major. Thanks for all you do. Ben, Indiana

[@markbrideau588]

Deer everywhere. 😀. Thanks for the quick summary on glacial lake Missoula.

[@dyannejohnson6184]

I really like your suppositions and questions. I love questions…

[@rayschoch5882]

I noted the horizontal lines on that hillside when I spent a night in Missoula on my way back to Minnesota from Glacier National Park and Spokane. Then I discovered “Nick from Home” and Ice Age Flood videos after I’d returned to Minneapolis, and the connection of the hillside to glacial Lake Missoula leaped immediately to mind. That interest hasn’t diminished after Geology 101 and its successor in the winter and spring of 2020-2021. Faint shorelines that are only barely visible are characteristic of glacial Lake Aggasiz here in Minnesota, too. Much flatter terrain, but the River Warren draining the lake was pretty sizable, and carved a valley far larger than necessary for the current Minnesota River.

[@angelacret]

Thank you Professor. It is always a pleasure to listen to your lecture, even when the "facts" are missing.

[@d.t.4523]

Thank you Nick. A lake that big will take a while to fill. That leaves plenty of time for shoreline creation. Good luck.

[@SCW1060]

Well Nick I guess it's safe to say by just looking at the hillside there it's just one piece of the puzzle and we all know how hard it is to solve a puzzle just buy one piece of it. As science Progreses I hope that one day that we can get a more definite understanding about what took place thousands of years ago in the northwest. This downtown lecture on the great floods is what got me addicted to your lectures and into your work. you have been a mentor of mine ever since and I'm so addicted to all of your lectures and videos thank you so much for keeping the dream alive and interesting to the new people coming up in geology I know if I took your geology 101 I definitely would have been a geologist thank you so much for what you do and for bringing us along with you to all of the most interesting geological features im the northwest

[@nolasmith7687]

Have to agree with you wholeheartedly..that’s how I got addicted to Nick..wish we had more teachers like Nick in every school system worldwide.

[@travis303]

I can't get enough of the ice age flood stuff. I find that so interesting.

[@heathertaylor4677]

I was through Missoula about a week after you were. I was on a trip to see Pompey's Pillar, Devil's Tower, and Mt. Rushmore. I was so amazed at the Gorgeous Rocks at Rushmore? Have you seen them? I had to collect a couple of them! Used my rock hammer for the first time! Thanks for your videos! It feels like a visit with a friend each time I view a new one! I bought a Roadside Geology Book of my hubby's home state to try to get him interested a little! I wish I could share the pix I took of those rocks! Amazing! You have helped renew my interest in Geology. Also, I love the videos with Randy Lewis! Thanks, again!

[@patkelley2190]

Nick it all good. Thank you for sharing this video and all of your work. Please keep it up.

[@cerberus2881]

Where you are was hundreds of feet under Lake Missoula. Very cool.

[@bradleyhannah8713]

I have collwcted rock all over the state of Washington . I did have clovis tools. CWU geology was enlightening for me with DR Ring I picked up the Roadside geology of Washington. I helped survey logging roads above Snoqualmie on the north side. Been to liberty and the green valley aluvial field. I found several "BLUES". Wish I could still hike around the mountains!

[@opheliadeclines]

Lucky we are in the age of drones!! They are getting us all over.

[@LillianArch]

My husband found a Clovis years ago as a little boy. He grew up in The Dalles. His dad had a load of River rock delivered for making a driveway. Pat was playing on the pile and found the spear point. It was perfect. Unfortunately, our house was burglarized years later and it was stolen. This was long before the points found at Yakima and Kennewick Man. Nick's new information adds to all the wonder I've felt since a young child growing up in the Pacific NW. I don't live there anymore but told my sister and brother-in-law who live in Hermiston I'm coming home next summer and we are all going on a geology field trip.

[@ever989]

Thanks for doing these types of videos. I find the questions asked to be some of the most interesting parts of your videos.

[@danielhawthorn2967]

i have wondered about those features for all of my adult life, and have found no solid answers. Thank you for showing me that I am not alone!

[@rickmarosi4546]

My understanding is the lines are spaced by about 35 ft in elevation, therefore a simple explanation would be they are annual fill lines eroded by waves. Always filling but surging in the spring & slowing in winter just like tree rings. So the winter slow fill along with the increased wind storms make the rings more pronounced.

[@SJR_Media_Group]

Nick Zentner, thank you for providing interesting geologic information in an easy to understand format. I look forward to your presentations and always learn something new. I have noticed similar marks on Rattlesnake Ridge and Ahtanum Ridge in Union Gap. I don't know if they are due to water, or some other geologic event. I know ancient Lake Lewis backed up all the way to Yakima and even Selah, but I don't know how deep the water was. The marks I see are hundreds of feet above the valley floor. They could also be the result of the many Flood Basalt flows, and the lines are due to erosion over time. The marks could be from erosion from the Yakima River as it carved its way through the Uplifted Anticline over a long period of time. Another explanation might be due to grazing herds walking parallel with the contours. However, the slope is very steep, greater than 100 percent slope. And, there is very little vegetation to graze on. The next time you drive through the 'Gap', take a look at the sides of the ridges. The marks are clearly visible, and even the Sagebrush grows along these lines. Thank you.

[@churlburt8485]

The grazing is what my father, who grew up on an Oregon ranch talked about once, but at that time, 60 years ago, people did not know if they were natural or had been formed by grazing sheep. Hope you find the answer.

[@bigskybob]

I went here and it's a fantastic school. Thanks for showing off the beautiful oval. We learned a lot about the floods in my Physical Geography class.

[@tedpeterson1156]

There used to be some American elms there oddly enough. I suppose those are all gone by now.

[@moreylongo]

Thank you for teaching us what you know and sharing the questions we don't have answers to yet. For the record, I vote that they are erosional.

[@richardbatistelli7280]

Another enjoyable walkabout, thanks professor. Richard, from Huntington Beach, CA.

[@josephmatherly7660]

Thanks teach, I have some property in Harker canyon nw of Davenport part of glacial lake Columbia. The floods ripped through to Cambrian marble and phyllite, Cretaceous granite, Tertiary sedimentary and pyroclastic maybe even some Precambrian greenstone..subduction zone along the Spokane River..

[@josephmatherly7660]

NE Davenport

[@robmagee100]

Facts are important because they allow the next level of questions, which open new discoveries, directions of exploration, and possibilities, and that is where the fun and inspiration is! Loving the questions!

[@jamesdriscoll_tmp1515]

Wonderful piece Nick, a calm reflection upon a deep subject. The dates of individual shorelines will be a real challenge. Set up a H. Bretts award for the first team to crack it, like the darpa challenge. Such a nice campus, but no crowds. True sign of the times. The deer browsing the lawn was a perfect close.

[@seanc6128]

That video you're referring to is how I learned that you exist, certainly glad that I found it back when I did. If I remember correctly I started from looking for stuff about the Bridge of the Gods as I live in the Portland area.

[@peacenow4456]

How great you're there. Love those great simulation videos. Yep, seen them all, so great!! I tell my family your glacial floods stories, often! Very awe inspiring! Keep encouraging those shoreline studies. You'll inspire someone!

[@littlebear8331]

"What we have done, we have done together!" ... a hidden message given by our Professor to his wife; you've got to love it.

[@hardrockuniversity7283]

I was just there yesterday. However, my wife was in the hospital, so I wasn't touristing around that much. Thanks for the info, I'll look closer when we are back in a week. BTW, she is recovering well.

[@c1osmo]

Hoping all goes well. As interesting as geology is the health of our partners has the more impact on our lives. Hopefully soon you will be able to wonder at those shorelines together.

[@hardrockuniversity7283]

@@c1osmo She is recovering well from the surgery and the Dr thinks he got all the cancer. Time will tell.....

[@c1osmo]

@@hardrockuniversity7283 excellent. Thank you for sharing. Big oz best wishes to you both. Oh and thanks to the medical professionals who study and work to get these results.

[@hardrockuniversity7283]

@@c1osmo I certainly couldn't re-arrange someone's insides- EHHHHHH! It definitely takes all kinds.

[@deantheot7296]

pretty campus, good questions, look forward to the next. Thanks Nick

[@glennkirchens7970]

Thank you sir for sharing your knowledge and insights. I've learned more from you than I ever learned in school, even when I was in a good learning environment. Keep it up sir. From the Great Lakes Watershed in NE Ohio.

[@nickynockyknackynoo2346]

Maybe time to take your questions further Nick? Sounds just the sort of thing that interests lots of people - not just Geologists. Perhaps a drone flight over the lines plus any recent papers or actual digging and lab analysis of dates? Keep on truckin' Nick. All good stuff. :-) p.s. If shorelines are not present on nearby hills (the ones not subject to Glacial Lake Missoula action) would that mean that the blown deposits - like Loess - might be expected to be on all hills, and therefore have been washed away - and not deposited? Just a thought.

[@joannepballard5170]

Thanks for the tour, Nick. I think I saw sheet or heat lightning in the skies now and then. One thing missing was a topo map. As you talked about this basin as a possible source for a glacial lake flood, I wondered what that looked like from an aerial view.

[@derekosborn]

Thanks for posting. Fascinating series of events that helped shape the PNW that we know and love. The Washington wine industry should watch this video. 😉

[@murrayf2890]

Always enjoy your shows. I have travelled through Montana Idaho Washington Oregon years ago and wondered how the landscape had been formed the scouring I mean. Thanks so much for your hard work plus your colleagues of course 😎

[@evelynmoyer9069]

This native Montanan enjoyed the walk on the campus, once again. Nevada has lots of old shorelines on hillsides especially near Fallon, NV by the ancient Lake Lahontan. Thanks!

[@frankevans6584]

Fascinating take. I too wonder how so many ,what we call hear in southwestern West Virginia, bench flats, were formed. They clearly appear to be old shorelines cut into our foothills of the Appalachian Mountains. I live along the Guyandotte River which is a tributary of the Ohio River

[@littlebear8331]

Thank you for bringing back memories of the flooding event prior to Memorial Day, 2001 at the Guyandotte River Campground near R.D. Bailey Lake. It served as a valuable lesson on how a river reminiscent of a babbling brook can turn into a raging torrent overnight; I still listen to my trusty weather radio to this day and I encourage everyone to do the same!

[@haroldgreer3639]

Lake Tight. Teays river.

[@jimwagoner4741]

Thanks for the video. Beautiful campus. I was there for a conference in August 2014. Would love to go back.

[@CTSFanSam]

May I suggest that the shore lines that are seen are not all of the shore lines created? I would think many shore lines would be erased by a successive shore line. Thus, we are seeing some of the shore lines, but not nearly all. I have seen this place in person. Pretty cool to think about the amount of water stored in the area back then.

[@Rachel.4644]

Sweet! Those lines were some of my family's first curiosities, decades ago. Fond recollections. 💕🤗

[@swirvinbirds1971]

Agree and as there was less and less ice as the sheets were melting the lake got lower and lower while still doing the flood and fills... Just not filling as much towards the end.

[@SawyerAndGretch]

Nick, hope you had a great time in my state of Montana....Squirrel! .....I would never knew about glaicial lake Missoula had it not been for you.

[@84Tacos]

Isn't Flathead lake a remnant of Glacier Lake Missoula? I was there on July 8th, 2021. Thank you for educating us in geology!

[@DanSpotYT]

That part at around 17:00 is very true. Some folks are simply b/w or 0/1 - and most anything outside of that is frowned upon. That's kinda sad in way. There are so many examples (I'll not bother to list them) where someone, some people asked questions, had wild speculations, etc., and those elements either turned out to be proven true later on or perhaps helped guide someone else to discover something down the line. Hope that makes sense. That's why geology is so interesting to me and many others. We know this and that, but we don't know or not sure of all this other stuff. Thanks again, Nick!

[@Fatspurios]

Interesting video. Always enjoy your teaching. UK.

[@kidchalleen4250]

Now you're on my home turf, Nick! I grew up in on the bottom of the dry Glacial Lake Missoula bed, wondering why the hills were as the were, why there were huge ripples and striations...it's actually why I have a deep interest in Geology was just looking at all the oddness there. The thing that confused my the most as a kid was the soils in the lake bottom (I didn't know about Glacial Lake Missoula until I was a teen)...you could almost tell it was sediments, but from what I couldn't fathom.

[@dyannejohnson6184]

I saw your video about the glacial drainage lecture some time ago

[@tgmccoy1556]

Based in Missoula during my days as an Aerial tanker copilot. Enjoyed duty there . Ditto Billings.

[@wendygerrish4964]

There was a Chinook Ch47 up at the Mariposa-Yosemite Airport on Friday. It had a big 'Billings' artfully painted on its side-there for fire fighting. Oh yep #561 working east of hiway120.

[@tgmccoy1556]

@@wendygerrish4964 that's the company name good operator.

[@wendygerrish4964]

Say TG (saw some neat clips of what you used to do via Juan Browns blancolirio chnl) Geology is my latest love.

[@tgmccoy1556]

@@wendygerrish4964 thank you. I was a DC-6/7 copilot did that for about 10 years .

[@wendygerrish4964]

We still had DC3s for top dressing in NZ 1970s. You've done it all. DC6/7 s amazing.

[@romans32426]

Thanks for the ride.

[@debramiller4098]

Thank you I’ll look as I lived in sw Montana over half my life . My adopted home. Fascinating information. I love every place in Big Sky Country. Thanks again

[@adriennegormley9358]

Oddly for a MT native I've only been to--and through--Missoula once in my life, back in 94 while en route from Bozeman MT to Marysville WA. Missoula was one of my two meal stops on that drive; the other was (drum roll) Ellensburg :-). Regarding letters on the hillside, I'm more familiar with the M on the base of the Bridgers outside of Bozeman (for Montana State University, home of the Bobcats), with its nearby B for Bozeman Sr High, which I attended until partway through my junior year when we moved to California. Someday, Nick, you ought to head over to Bozeman; just a wee bit northwest of there, is a place called the Horseshoe Hills. Not for the layout of the hills themselves, but for the rich fossil beds of trilobites found there (but watch out for the timber rattlers, they can get feisty). This is at the base of the Little Belts, where they meet the Bridger Range. Fun, though, in spite of the somewhat feisty local reptilian population.

[@haroldhahn7044]

Each shore line represents a windy day with big waves, while the water level was at that height.

[@vinmansbakery]

Nice with the 🦌 at the end!

[@robertwhite6939]

I like this style of video the best chill with a peaceful end .

[@Plantagenaut]

Thanks, Nick! Stay hydrated, my friend! I have enjoyed your video's (but, not the classroom) ⛰

[@rinistephenson5550]

Now I want to go to Missoula! Thanks, Nick!

[@Chompchompyerded]

Could they be seasonal? Maybe representing deposits dropped during the spring melt each year over the course of several years? Or maybe where freshwater icebergs abraded the shore? If you had big ol' icebergs bumping up against the shore and melting, it could be both erosional and depositional. I wonder if you could take a backhoe and run a trench down the side of a hill where those occur to see what shows up? It would be interesting to know if there are any erratics either big or small deposited on those hills. Damn I wish I was able-bodied and about 40 years younger. I'd love to do that project. It sure is a problem being someone with endless curiosity and and no means deal with it. Also, why does life have to be so short? There's not nearly enough time to fully explore all the things that I want to learn about.

[@TheMadness51]

Those beach lines are eerily like the lines at the tip of the lower peninsula of Michigan. Some of that story may have been covered up by the the Valders advance before the final retreat of the ice some 14k years ago. It's a heck of a mystery ya got on your hands Nick. I gotta stick with my surface geology here to figure out if any amounts of gold got laid down in beach lines of glacial Lake Saginaw. Cheers!

[@geoffreynewton5839]

While my interest in geology was what started my following of your videos, I am just as appreciative of the visions of the general landscape and vegetation of this part of the world. Somewhere I’ve long wanted to visit and considering the Covid world we are living in at present, maybe this KZbin tour is as close as I’ll get?

[@djenebasidibe468]

Nice stroll around campus at the university of Montana. :) I can even sort of imagine the refreshing evening breath. :) Absolutely enjoyed it. Thank you Nick for letting us join you in some sort of way.

[@harti938]

Maybe the shorelines are fillmarks. Could be that the refilling of the lake occured seasonally. Depends on how long it takes to make such a shoreline last, to be noted today...

[@Anne5440_]

It's so important that you keep asking questions! I think there will be new qeologists because of your questions and the questions of others. I have been to Missoula many times. My favorite encounter with Lake Missoula was many years ago when we made a trip to the National Bison Refuge north of Missoula. While driving around there we came across a sign that talked about Lake Missoula. It was placed at the highest shoreline way up the mountain. You could look across the valley and clearly see the shorelines at various levels. That day was also my first sighting of abig horn sheep. Keep exploring and sharing, I love these adventures. Stay curious!

[@Eric_Hutton.1980]

Life would be a dull thing if there weren't mysteries in the world.

[@SweetSunrising]

I'm here for the questions! It adds an element of curiosity & mindfully engages me with the topics in discussion.

[@annieaspholm3534]

Now you are in my neighborhood! YES! Come see the Glacier Moraines in the Mission Valley.

[@danoconnor3720]

In Salt Lake City you can look up to the hillside and several hundred feet up you can clearly see several shore lines.

[@TheMadness51]

Dinnit Bonneville create that?

[@danoconnor3720]

@@TheMadness51 Yes.

[@douglasdunn7267]

Thanks so much Nick for your efforts on the Missoula Floods. I was under the impression that one of the big Ice Dams was at or near Plains, Mt. After spending time in the area and looking at the huge flow marks and sand dune deposits in that area, one could see clearly the results of massive flows passing through that narrow valley. This topic has always held my interest and it's great to see more effort to place these floods in time. I wonder how the fishing was in Glacial Lake Missoula? I love your programs and would have enjoyed being one of your students!! I'll continue to follow your adventures.

[@sidbemus4625]

Thanks Nick...Keep asking questions sir......

[@Sköldpadda-77]

I enjoy your thinking out loud geology sessions. I like to get a glimpse of How a geologist thinks, how they work things out, as T. C. Chamberlin and his multiple working hypotheses would have one do. Or, as Richard Dawkins once said in an interview, “We like to say ‘I don’t know’ because that gives us something to do.” After all, if we already knew everything, what would be the point of science, or indeed any intellectual endeavor?

[@wendygerrish4964]

That was soo cool! An interesting challenge to figure out the mechanism for receding stepped Lake elevations. On a miniature scale the lowering of Reservoir levels during and after the spring runoff on Lake Don Pedro reminds me of this process.Not hard to imagine giant Boulder carrying icebergs rebuilding icedams though. (Sorry no data Townie sitting with a cup of tea in the back garden on such a lovely day). Looking forward to more on this from the October field trip team.

[@jackswisher3171]

Fred Phillips at New Mexico Tech in Socorro has a work-around to date depositional cobble bars by cosmogenic nuclides. I'd like to hear you interview him.

[@jimnelson7740]

After the floods from Lakes Missoula and Bonneville, Doc, you just drove through the flood zone of the 3rd-ranked flood in world history. It came down the Big Lost drainage from Copper Basin. The water was 60' deep at Arco, and their are large anomalous boulders out on the desert floor southeast of Arco, and much non-basaltic gravel deposited in that area. yet, I never even hear that flood mentioned anywhere. Don't even know if it has a name, or if the lake it came from is named. I think it was investigated by a geologist at the Idaho Lab. His paper is what made it known to me.

[@hillaryhodges1695]

I would love to read that paper and more about that flood. Can you put up a link to the paper?

[@jimnelson7740]

@@hillaryhodges1695 Hill, I'll try and find it. haven't read it for several years. Got a lot on my plate right now, so be patient.:-)

[@jimnelson7740]

I found it, but the link is really long. Just do a search for "Big Lost River ice-age flood", and it will come up. Jim

[@dancooper8551]

Beautiful campus!

[@kyleroth1025]

Thank you Professor Zentner

[@paulmacfarlaneslp9209]

I don't see why the various benchmarks can't be different stages of filling ... and while tne lake existed it probably froze deeply, and then heavy winds pushing against the frozen surface each year of filling would have plowed heavily against the shoreline creating springtime ice erosion and berms, like mini moraines.This phenomenon is frequently observed.

[@KSparks80]

They do have a pretty campus there. Although at the moment, I think any campus that wasn't a toasty 112 degrees would look pretty good.

[@opheliadeclines]

Great the way you suggested a future geologist can earn their wings by studying the age of the deposits downstream.

[@annieaspholm3534]

Those lake rings, go east a ways.. Like Warm Springs.. And over past Hamilton.. Very cool

[@eidrith493]

Asking questions gives the window for answers to be found. Has any Brian Attwater type dug long trenches covering several lake margin lines to see what changes in sediment types occur right on the old shorelines?

[@peterdaymond6080]

It is good for Geology teachers to ask questions of students and other teachers. If only Archaeologists would do the same

[@JSchrumm]

Thinking maybe the Okanagan lobe lifted and slightly drained every season until failure maybe draining more at some seasons than others to create individual shorelines. But I was once a 16 year old hippy.

[@thedissidentcitizen]

AHA ! Professor Zentner, I have been seeking you for some time now and alas, here you are ! Glacial Lake Missoula - one of my most favorite subjects. I have an interesting concept that I have heard no one speak of concerning the Glacial Lake Missoula floods. The Columbia Gorge. [Some] of the gorge was carved by these floods; I understand this. But, before the floods carved the gorge, where did the water go ? I think that, before the Columbia Plateau rose, and the Cascade AND Sierra mountain ranges rose also, that the initial flood waves were big enough and tall enough to splash up and over the "Blue's" at or near Umatilla and travelled south along the eastern slopes of those two ranges and sculpted much of the land all the way down to the Gulf of California. Looking at a view from way high up, as with viewing the scablands from a similar altitude, down this "route", one can [plainly] see a definitive line of massive erosion from Umatilla to the Gulf. Much of this "route" follows U.S. Highway 395 South down to east of Barstow, San Bernardino, through the Salton Sea and on to Mexicali and the Gulf. What think ye on this Professor Zentner ?

[@thedissidentcitizen]

And then we have the enigma of the Snake River Valley. Could it initially have been "formed" during the Pinedale Glaciation epoch when, possibly, the Yellowstone "hotspot" erupted and instantly melted the glaciers covering that area and caused a massive flood event. I understand also that Lake Bonneville, which was also mega-gigantic, reached a level that allowed it to flow over a small rise to the north of there and subsequently into the Snake valley in a massive outpouring that aided in sculpting Hells Canyon and then on into southeast Washington state where it eventually joins the Columbia River at Tri-cities and on to the Pacific Ocean. The outpourings of lava in the central part of Idaho may have also been covered by ice as well adding to the deluge(s).

[@hjpngmw]

1. If those aren't shorelines, I'd like to know what they really are. 2. What a beautiful campus. 3. As always, thank you for showing this to us.

[@richardmourdock2719]

Nice recruiting video.... Hope it fires the imagination of an undergrad or grad student. I like the idea of the "wave action" cuts helping to create the terraces and don't find that thought at all contradictory with various periods of "lake level rise" and very rapid "drops due to ice dam breeches, cracks or movements. I don't see why such changes at the dam(s) couldn't be almost seasonal. Erosional of ice dams in the spring and summer.. fall and winter slows the seeps and cracks....

[@drakereed9537]

Nick, I very much enjoy your videos. I am from Helena so this is kind of a special treat. My understanding is that the ripples were deposited as Lake Missoula receded. Ripples like you see on a beach as the tide goes out or on a river as the flood waters recede... only on a much larger scale. I get that this is not proven. How close are you to the notion that the ice melt was caused by the heat produced by a comet strike or near miss. Locally we have Ten Mile Creek which on a smaller scale shows evidence of a catastrophic glacial ice dam failure, which I believe is thought to have occurred around the same time as the Lake Missoula event.

[@twotone3471]

One would think it possible to use the sediments on the floor of Lake Missoula. As the lake filled, the sediment would have been finer, as the source of the sediment would be further from the lake bed, so you should get some grading in the sediment if the lake was emptied and refilled over and over. Or a single layer, with generally finer sediment until the breach. It might also be possible to detect ash deposits from dated eruptions. So do not give up hope, the answer may have been under your feet, instead of above you.

[@guiart1553]

…and every time the ice dams collapsed the erosive force of the water would erase old features and create new features so down stream topography would be reset to some extent with every episode which might confuse the dating and sequence of the flood events.

[@laurencelance586]

Facinating topic! Has anyone dug down in each level to see if the soils or gravels are different in composition or type?

[@MarkLaPoint]

Interesting terrain there. Flathead Lake. I’ve wondered if that flood water found it’s way into the Great Salt Lake Basin.

[@churlburt8485]

no, elevations wrong. see Lake Bonnivle (spelling?) flood water ran north into the Snake River

[@skippylippy547]

Very helpful video, thank you! 😃

[@jamespmurray4059]

Thanks for showing us this. No glacial lake Missoula is folley.

[@adem-Savs]

Treat each relict shoreline as you would a sedimentary strat column. Each will have a different height, which could be matched to similar divisions across the ancient lake deposits, steps or berms on a regional scale. Yu may find evidence in other locations of they are indeed erosional or depositional features.

[@Formula400Pontiac]

Winter ice on this ancient giant lake would make huge marks in the hillsides compared to the wave action. I'm not saying that the erosion from waves are insignificant but ice tend to disturb shorelines much more efficient. You all have probably seen videos of ice sheets forced onto land by wind and how it can bulldoze large rocks and gravel into huge gravelbars. There are huge forces in action even without factoring in the effect of wind on the ice. What i'm trying to advocate is that this so called shorelines may be a seasonal erosion event on a growing ice-age lake Missoula and not a flood event deposition mark

[@macjam100]

We're finally here thank you thank you

[@petrichor649]

Thanks Nick

[@loslaynes]

Alright, Griz Country. Go Bobcats! When I took Geo 101 2 and 3 in 1978/9 at Montana State (Bozeman, yes Bobcat country) I couldn't wait to get back to Missoula in the summer and walk on those beach terrances. Yes they are faint. But there are other places in Montana to see them... Glacial Lake Missoula had a huge impact on the recent geology of western Montana and downstream.

[@dyannejohnson6184]

Thank you

[@Ryanboy2020]

Nick, if I may, the issue people are having the most difficult time with is that there isn't enough water in the Missoula Ice Dam theory to cause the catastrophic erosion you and many other geologists from Bretz to Atwater have noted in the channel scab lands. There would have to be multiple floods with both errosional and depositional characteristics in the Missoula lake/flood plain. However, the "multiple" catastrophic flood theory is NOT supported by what we see in Moses Coullee and other massive cataracts. There is evidence of just one catastrophic flood? These are the unanswered questions that need to be resolved for us to understand how and how many times this region has been catastrophically destroyed by floods. The most important question then is, what source of energy is needed to obliterate the massive ice sheets that lay over most of North America and Canada at that time? 10 miles deep of ice? What could melt that in what some have suggested in days or weeks, and send massive floods through the northern continent out into the Pacific Ocean?

[@zazouisa_runaway4371]

Thanks Nick 😊

[@Tookewlpara]

Is it possible that the different sedimentary levels could be due to seasonal evaporation The Lake Mead water issue makes me wonder

[@PrincessTS01]

i recognize that building, my daughter had her high school graduation there. lol I took 586 photos on that trip.

[@reneestearns6636]

A good teacher indeed. Always question.

[@davearmstrong3775]

Come back in winter and you can really see the water levels :)