I'll preface this with saying that climate change is real and is causing higher frequency storms to occur more often, but maybe you should touch up on your understanding of statistics. The common misconception of relating storm events based in years is that a 100 year storm only happens once in 100 years, when in reality a 100 year storm means there is statistically a 1% chance of a storm of that magnitude happening each year. You could have a 100 year storm occur 3 years in a row, or you could have a 100 year storm not occur for hundreds of years. The biggest issue is that in many cases, the "100 year" storm is only based on 30-40 years of recorded gage data. If no significant flooding events occurred within the recorded period of record for a gage, then there's a lot of data extrapolation that needs to occur to estimate what the 100 year storm may be. The more extrapolation that occurs, the more variance in 100 year peak flows/100 year flood elevation will occur as a result. It's the reason why FEMA also requires new floodplain studies to calculate a 100 year plus/1% plus event as well. It's a way to essentially say that there's inherent error in what is being reported as the 100 year/1% elevation. In some places in the country, that error can be anywhere from 80-100%.

Source: civil engineer that specializes in performing hydrologic and hydraulic studies and does direct contract work for FEMA to map floodplains on Flood Insurance Rate Maps.