Glacial Lake Missoula Questions 

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 RU-vid 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

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.

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

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

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

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

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

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!

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

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!

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

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.

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.

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

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.

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!

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

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

Nice with the 🦌 at the end!

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

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.

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

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.

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 😎

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!

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.

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

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.

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.

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!

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

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

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.

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

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.

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. 😉

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!

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

…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.

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

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.

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!

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.

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!

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

We're finally here thank you thank you

Interesting video. Always enjoy your teaching. UK.

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.

Thanks for the ride.

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

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

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

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

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

thank you so much for your work!

Beautiful campus!

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

Love the questions!

Thanks Nick

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

Thanks for sharing Prof Z!

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.

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.

A good teacher indeed. Always question.

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..

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.

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

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

Thank you Professor Zentner

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.

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.

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.

These are fantastic videos

Thank you

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.

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...

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

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.

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.

Thanks Nick 😊

Very helpful video, thank you! 😃

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

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?

It’s a sad truth that some people have developed an ignorance towards Science. It’s my opinion that it is to their own detriment as they are really shooting them selves in the foot, so to speak, as they must be using a developed technology that was created due to Science in making these comments. Thanks Professor Zentner for sharing your knowledge and quest to continue learning with those of us who enjoy the process. Never stop learning and pushing our own limits on understanding the world/universe in which we exist. ( I included the Universe as I, personally, am constantly expanding my own understanding of astronomy and astrophysics along with your guidance about geology ) #Science !

> There is a significant difference between the relatively flat "slack water" deposit areas of Glacial Lake Lewis and these steep slopes in Missoula. The former provide some protection from weathering, thereby enabling future analysis, and the latter invite the very next storm (after flood-draining) to wash away recent deposits. The deposits you needed here for analysis may have washed away centuries ago. > It is likely that continental ice sheets had winters and summers at their edges. Seasonal changes in one year might change water levels in (an otherwise undrained) Glacial Lake Missoula and leave cuts at different elevations. As such, I'm not buying the "1 edge equals 1 flood" theory.

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.

thanks nick

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!

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

Welcome to Missoula:)

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.

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 ?

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.

Eunjoyed it. Neuver imagined a sea!

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

Randall Carlson's Kosmographia channel has focussed on Lake Missoula, the Ice Dam theory doesn't hold water, the physics will not allow ice to hold back the quantity of water that would have filled the basin. There was a Lake Misoula and floods of a scale we have not seen since the the Clovis people disappeared from North America, boulder fields, scablands and places like steamboat rock are the remnants left overonce the water receded, gr8 channel Nick love your work

Hey Nick, I just wanted to say that you beat out Stephen Colbert for my view. You kick ass. Thank you for sharing this. you seem kinda exhausted. Take care of yourself - you're an excellent teacher and we don't want to lose you.

Thanks for sharing. I am a long-time glacial Lake Hitchcock guy.

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....

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?