[tacticalogic]

Water seeps into the cracks and crevices, freezes and expands (like a soda bottle left too long in the freezer), burst, and splits the rock apart. Heating from the sun also expands rock, which then cools and contracts at night. Repeated cycles of this also weakens and breaks down rock.

And if that's a critical part of he erosion process, then you can't really have "rapid erosion".

[ETL]

And if that's a critical part of the erosion process, then you can't really have "rapid erosion".

There are many forms of erosion, some near instant, others over thousands or millions of years. In any case, it's rapid as opposed to the usual erosion process. Boulders can and do break free from cliff sides rather rapidly as a result of freeze-expansion.