This book by former Geology professor David Alt is an excellent resource:
Here is the link to the book on Amazon: https://www.amazon.com/Glacial-Lake-Missoula-Humongous-Floods/dp/0878424156/ref=sr_1_1?crid=3PVDWHVYFB5BH&dchild=1&keywords=glacial+lake+missoula+and+its+humongous+floods&qid=1613529100&sprefix=glacial+lake+miss,digital-text,261&sr=8-1
At its highest level, Lake Missoula held an estimated 500 cubic miles of water. When it breached the glacier damming the Clark Fork River in Northern Idaho, all of that water was released over an estimated three day period across Eastern Washington. I was so sudden and wide spread that likely nothing living in its path survived. My wife and I have driven over a good portion of the floods path from the source to many of the parts of Washington that were reconfigured by the deluge.
The panorama below is from photos I took at the Dry Falls in central Washington in 2013. It was formed by the floods as Glacial Lake Missoula emptied and refilled, possibly dozens of times towards the end of the last ice age. The insert is a scale photo of Horseshoe Falls to indicate the extent of the flood waters over Dry Falls.
The next photo is an overview of the area form Google Earth with Spokane in the upper right and Moses Lake just right of center at the bottom. The tiny bright green bar left of center about 1\4 of the way to the top is the extent of the panorama. The large swaths of brownish gray are areas eroded by the ancient floods, leaving small remnant lakes dotted across the landscape, and show that only a portion of the waters passed over the Dry Falls.
The last photo is a closer view, again the green line indicates the area covered in the panorama with the tiny gold bar indicating the area of the Horseshoe Falls insert in the Panorama.
I've been driving through some of these areas since the mid 1950's as we drove from Helena to visit family in and around the Seattle area. My dad first stopped at the Dry Falls when I was about six and explained what we knew about it at the time, that it was an ancient waterfall. I still marvel at the fascinating, harsh but beautiful landscape and imagine the tremendous powers that created it every time we pass through.