Happen along

"Now, if a rattling good earthquake were to happen along, you might awake in the morning to find yourself on an island, or even under water."

"[W]e can't 'spect a cyclone to happen along and take us to the Emerald City now."

Novae, or new stars, are always happening along.

"Well, you're the one who's always telling me not to leave my purse in the cart, and that's probably what that woman had done, and someone happened along and just took it."