in some instances, future predicted changes in short term rainfall extremes have been misreported as historical changes. a theoretical one-standard deviation shift in mean extreme rainfall intensity has been misreported as environment canada data, suggesting that storms occurring every 40 years are occurring every 6 years", based on a standard, normal probability density function (see presentation 13:10). it has also been reported that 20 times more storms are occurring than 20 years ago, and that this is affecting urban flood water damages and insurance premiums - eccc has commented that there are no such significant changes in storm patterns.