You may not know this, but wisteria pods can pop as they dry. Mine are going crazy right now, popping with such force that I'm worried a seed will break a window. For more information about this phenomenon, check out this webpage. This afternoon, my neighbors Bob and Ben and I watched as the pods released their built up pressure. I don't remember them doing this last year--I suppose the temperature has been just right to make this happen.
Before:
After:
