— More and more traffic management techniques, including accounting and load adaptive routing, try to take advantage of the fact that traffic demands are consistent with Zipf’s law. By treating a few large volume demands differently they try to capture most of the traffic. This relies on the implicit assumption that traffic demands are persistent in volume over time; meaning that their volume does not change drastically over time. As this assumption has been shown to be incorrect we in this paper focus on how Internet flows behave over time. Accordingly, this paper examines the characteristics of volatility in a qualitative way by characterizing the components that are responsible for changes in the cast of heavy hitters over time.