Is the trunk is cracked / the tree split down the middle an emergency?

What changes while you wait

If the crack is over a bedroom, a porch, a patio or anywhere people sit or sleep, treat it as now and stop using that space tonight — split unions fail with no warning sound and often in ordinary wind or simply under the added weight of a soaking rain, not only in storms. A closed, sealed, long-standing frost crack on an otherwise vigorous trunk with a target-free drop zone is a legitimate watch-and-monitor item. The single question that separates the two: do the sides move independently of each other?