Hypercane
The word hypercane was coined by Kerry Emanuel at MIT to describe a regime when the simple thermodynamic model to estimate hurricane intensity fails to converge.
Solving the equations by numerical methods indicates that in that regime, phenomenal storms are formed that reach 20 miles high, 10 to 15 miles across[1](though under special circumstances it may become as large as a continent.) with winds approaching 500 miles an hour. It is also said that storms of this rank will not dissipate until an ample amount of time passes.