It happened not on Shabbos

This coming Shabbos will be Shabbos Hagadol because of a נס that did not happen on Shabbos. Which Neis ? Because the נס of crossing the Yarden didn't happen on a Shabbos, we have Shabbos Hagadol. The ב"ח (O.Ch.430) writes:  why  do we commemorate the נס (sheep tied to bed ) on Shabbos instead of  the tenth of Nissan. He explains so as not to confuse it with a different נס that also happened on the tenth of Nissan.  The crossing of the Yarden happened on the tenth of Nissan but not on Shabbos.  By commemorating the נס (sheep tied to bed ) always on Shabbos and not on the10th of Nissan no one will think we are celebrating because of the נס of crossing the Yarden.