Meet the work of C. H. Wellington, cartoonist mislaid by history. He specialized in finding the humor in the moment between the recognition of one imminent disaster and the realization that it will soon be followed by a worse problem.
It's funny because it happens to other people!
The board doesn't seem to be ready to break; it's just making a board sound, and misfortune can be easily avoided by shifting the weight to the beam. But it's taken his mind off the task at hand.