Not a flash flood, 2012
Here is a hint as to why we were stymied. As close to a flash flood as I have yet seen. We couldn't tell how deep it was, but it was moving FAST! At times I have made the crossing barely getting my feet wet, at worst.
Here is a 2012 video. My impression was that it was probably crossable in 2013, with considerable risk of falling and getting completely wet, but not washed downstream. Does this 2013 video bear me out?