Almost two weeks ago, I shared some images that were taken when we took our son and daughter on a trip through the National Bison Range here in Montana. We went there because we were getting ready to celebrate our 40th wedding anniversary and our son had made the long trip from Southern Oregon to celebrate with us. Neither he nor our daughter, who has lived here for nearly a decade, had ever been to the NBR (National Bison Range).
Established in 1908, the NBR isn’t especially large, covering an area of about 18,500 acres. However, it is home to American bison, elk, pronghorns, bighorns, black bears, grizzly bears, coyotes, deer, eagles, hawks, and many more wild animals. It should be stressed that the animals are totally wild. In fact, there are few areas in the refuge where people are allowed to exit their vehicles because of the danger posed by the animals. The first image is one of those areas where it is safe to get out and walk around, and it is a good thing because the view is breathtaking.
This is the highest point in the NBR that can be reached by car. My wife and son are looking out over Mission Valley. It isn't hard to see how large this valley is, though this is only part of it and there is also another large valley on the other side of the NBR, in the direction opposite of where I took this picture.
Perhaps the most astonishing thing is that the entire valley was once the bottom of a gigantic lake and where we are standing would have been the top of an island in that lake.
This image shows even more of the Mission Mountains. This is to the left and more northerly than the last picture. I'm trying to give an idea as to the scope of the lake when it existed. The valley is obviously fertile and that is largely because of the lake bottom sediments that cover it.
This picture is to the northwest. Although it is lost in the smokiness of the distance, at the far end, there are yet more mountains that formed the northwest end of Lake Missoula. Keep in mind, too, that these pictures were taken from what would have been an island and none of them show the valley in the south, southeast, or southwest of the NBR. Saying that the lake was enormous is vastly understating it.
This is about the closest that the images come to showing the view in the 'other direction'. This is the view to the southeast of the other images. However, it is also deceptive because this is taken before we reached the summit, so where the picture is being taken and everything else in the picture except for the distant mountains on the horizon would have been underwater 11,000 years ago. The picture also doesn't show the vast valley between the hills in the middle ground and the mountains on the horizon. Our distance from this image to those far-away mountains is about 60 miles.
Also keep in mind that all of the images in this series are from high up in the NBR, near the highest point in the refuge. I still have difficulty in wrapping my brain around how huge Lake Missoula was. Incidentally, the river valley I live in, located roughly 40-50 miles from the NBR, was created primarily by the repeated draining of the lake. This is a river valley, so the Clark Fork River has done some sculpting of the landscape, however, most of the formation was done from the staggering amount of water that flowed during the many times the ice dam broke up and subsequently reformed.
Up here on top, there are three plaques. I took a picture of all three, but one of the pictures didn't turn out. This is the first one, though. The plaque reads:
The Mad Rush to the Sea
Lake Missoula, which formed behind a glacial ice dam along the Clark Fork River about 15,000 years ago, would rise year after year until it finally became deep enough to float and break the ice. When it broke, the lake suddenly drained, dumping its water across eastern Washington and down the Columbia River to the Pacific Ocean. Because glaciers were still moving south out of Canada, new ice dams formed, and broke, time and again.
Between Plains and Thompson Falls, Highway 200 passes through 10 miles of nearly straight canyon. When the largest of the glacial lakes was draining, careful calculations estimate that the flow through this area was at least 9.5 cubic miles of water per hour. That is more than 10 times the combined flow of all the rivers in existence today.
When the lake drained, enormous volumes of water poured through three passes a few miles west of here. You can travel across miles of the giant ripples that formed under this tremendous flow along Highway 382 near the north end of Camas Prairie. These look just like sand ripples in a creek bed, except they are as much as 30 feet high and span 200 to 300 feet from crest to crest.
~David Alt, Author & Professor of Geology
This plaque is an artist's depiction of Lake Missoula, from the same vantage point as the first picture in this set. Even with the painting, it is hard to grasp the amount of water that filled this valley. The plaque reads:
You are looking east across the Mission Valley to the high and deeply glaciated peaks of the Mission Mountains. The artist's reconstruction shows the same scene as it surely looked 11,000 years ago when Glacial Lake Missoula flooded the valley. Also during that time glaciers that filled the valleys spilled into the lake, snapping off and forming icebergs.