There are plenty of good reasons for uncontrollable laughter. A moose huffing car exhaust is one of them. "Just because" is totally one of them. Sometimes a single word is all it takes. That's what happened to one news anchor in the above clip.
The broadcast from Tulsa's KJRH was airing a segment about an orphaned and rescued beaver named Rocky. Before throwing to the next segment one anchor started tossed the word beaver around carelessly. That is guaranteed to end in an innuendo-laced sentence. He makes it happen a couple times before breaking through his cohost's defenses.
The laughter starts and can't be controlled, even as they go to weather. It seems like things have calmed during weather. But when they cut back to the anchors, things have gone poorly. They're still fighting laughter and wiping tears from their eyes.