No matter where you are sitting in Missoula right now, you are at the bottom of a lake. It may be a lot dryer than you expected, but it is true. During the last Ice Age, a huge glacier plugged up the Clark Fork river, and created what is known as Glacial Lake Missoula. You can see evidence of this massive lake, every time you hike the "M" or Mount Jumbo. The horizontal lines in the sides of the mountain, are actually the former shorelines of the lake. The lake filled up and emptied many times during the ice age. The YouTube channel, Ice Age Floodscapes, recently shared an amazing video that explains everything you need to know about Glacial Lake Missoula.