Is my tree splits into two trunks and it looks like it's coming apart where they meet an emergency?

What changes while you wait

Escalate to a same-day call if you can see a crack running down out of the notch, if the seam is visibly wider than it used to be, if the two stems have shifted relative to each other, or if you hear cracking in wind — those mean the union is already failing. Absent that, a sound union with included bark can stand for decades and many never fail at all. What moves the clock is weight accumulating at the ends of the stems, the included seam getting deeper every season, and water sitting in the notch rotting it from the inside. The danger is that failure is not gradual — it is a storm event, and central Indiana's straight-line winds and wet spring snow loading are when these let go.