I agree its possible that this could be a series, but does each of the storms meet the criteria to be classified as a derecho (MCC - mesoconvective complex) not just MCS (meso-cyclonic storm) see one definition here http://snrs.unl.edu/amet451/miriovsky/what.html. I guess its up to the federal weather agencies to determine this. The northeast of Ontario was no doubt hit with a progressive derecho, no confirmation of any tornadoes.