Some five years ago we flew to the Domincan Republic. About 2 hours out from Punta Cana we experienced incredible turbulence the likes of which I do not ever want to experience again. Basically the aircraft kept shaking then dropped like a stone for a few seconds and then just as it recovered did it again and again for what seemed an eternity. Even the cabin crew had white faces and some passengers were physically sick.

We found out on arriving that we flew over the remnants of Hurricane Ivan!

Serious Scary stuff.