Absolutely wrong in so many ways.
Have you never seen the Grand Canyon? It's geology? Read about it? Even schoolchildren do an exercise to determine how long it took to cut it. And it's all easily verified if you want to attempt it.
Oh, and, by the way, Mt. St. Helens canyons are not composed if sedimentary stone, limestone, or granite, they are layers of mud and ash. Again, the facts are all easily verifiable, even by schoolchildren.
The channels at Mount St Helens are cut through unconsolidated ash. How can this be compared to the situation at the Grand Canyon?
Really? Who?
a column which is only theory I might add and has never been observed in nature.
You are mistaken. Read and learn: The Geologic Column and its Implications for the Flood .
Note that the author, Glenn Morton, was once a young-earth creationist. As he began actually working in geology, however, he realized that what he saw in the field could not be reconciled with the falsehoods that his YEC teachers had told him.
Have you studied Mt. St. Helens and the Grand Canyon in detail to see how they were formed?
Yes.
There is no possible way the Colorado river formed the latter,
You forgot to explain why.
but the former gives clues how a canyon could form very very quickly.
No it doesn't, unless you think you can find steep canyons cut through ash (or mud) which reach a *mile* deep without collapsing.
Why not? Be specific. "Show your work"