"By showing that the frequency of occurrence scales as an inverse power of the severity of the event, and assuming that this relationship holds at higher magnitudes, we are able to estimate the probability that an event larger than some criteria will occur within a certain interval of time in the future. For example, the probability of another Carrington event occurring within the next decade is ∼12%."

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2011SW000734