Scott,messing with a beaver dam is illegal in many states--thus breaking a dam open can result in charges being brought against you.
Breaking a dam when the ice is frozen can also result in the loss of all the beaver,plus any rats that are also inhabitants.
Even in open water,and working damage control beaver-when dam breaking may be used--I avoid it.Working beaver with stable water conditions,is a lot easier.Rising and falling water is a real pain.
Tom