The Scablands were terraformed by a series of GLOFs (Glacial lake outburst flood) like this when deglaciation started at the end of the last ice age. Just imagine it on a thousand times bigger scale

>During the last deglaciation that followed the end of the Last Glacial Maximum, geologists estimate that a cycle of flooding and reformation of the lake lasted an average of 55 years and that the floods occurred dozens of times over the 2,000 years between 15,000 and 13,000 years ago. U.S. Geological Survey hydrologist Jim O'Connor and Spain's Museo Nacional de Ciencias Naturales scientist Gerardo Benito have found evidence of at least twenty-five massive floods, the largest discharging about 10 cubic kilometers per hour (2.7 million m³/s, 13 times that of the Amazon River).

https://en.wikipedia.org/wiki/Channeled_Scablands

https://en.wikipedia.org/wiki/Missoula_floods

Also it's interesting if you start reading about Native American flood stories, these were not just tales or legends but telling actual historic events that the ancestors experienced.

https://en.wikipedia.org/wiki/Missoula_floods#Early_flood_st...