This has happened here in the USA many times in the past. You have to read how big they were as it was incredible the massive amount of damage that was done. I imagine man caused this by using fire which caused global warming.
Missoula floods
https://en.wikipedia.org/wiki/Missoula_floods
Lake Missoula
https://en.wikipedia.org/wiki/Lake_Missoula
Click on Images. Many photos and graphics showing the height of the wave - over 400ft!!
https://media.winefolly.com/missoula-floods-size-ice-dam1.png
That is 400ft and more!
