occurred near Mulhall, Oklahoma on May 3, 1999 indicate that over the $8$-minute observation period the exponent $\alpha$ was in the range $0.5$ to $0.6$, although “the decay rate was sometimes closer to $V\propto R^{-1}$” [@wurman02]. The results of the analysis of data collected from an F0–F4 tornado that occurred in Harper County, Kansas on May 12, 2004 indicate that over the $13$-minute observation period the tornado intensified while at the same time $\alpha$ increased from $0.26$ to $0.61$ [@kosibatrappwurman08].

These results strongly indicate that established tornadoes exhibit a power-law decay in the tangential velocity and that the magnitude of the exponent correlates with the severity of the tornado. This is consistent with some of the authors’ work [@belik14], in which Serrin’s “swirling vortex” model [@serrin] is revisited and solutions to the Navier–Stokes and Euler equations are sought for which velocity is proportional to $r^{-\alpha}$ with a general positive $\alpha$. It is shown that only solutions with $0<\alpha\le1$ are physically reasonable, and that more violent storms would correspond to larger values of $\alpha$ and less violent ones to smaller values of $\alpha$.

Some justifications and explanations for the power laws in tornadoes can be inferred from existing literature. For example, 