Certified arborist and urban forester here,

The crack has been present for sometime judging by the compartmentalization that has occurred in the branch union. However, further down along the crack shows an obvious unstabilized crack that is progressing and would be considered an actively occurring failure.

Since you mentioned this is heading towards you house, this is an absolutely high risk tree with major consequences if it fails... which it is actively doing. Call an arborist ASAP if you haven't already.

To people that have mentioned cabling and bracing the tree, it is most likely past the point of salvaging. It may have been an excellent candidate for cabling and bracing a year or even a few months ago before the crack had progressed, but now it's to a point where the cabling would just be a temporary bandaid.