Annual exceedance probability curves, represented by the bolded black curve, measured in meters or feet relative to the Mean Higher High Water (MHHW), Mean Lower Low Water (MLLW), or Mean Sea Level (MSL) datums, along with 95% confidence intervals. Blue dots represent annual highest or lowest water levels after removal of the Mean Sea Level trend.

The exceedance probability curves were calculated using the Extremes Toolkit software package which fits the Generalized Extreme Value (GEV) probability distribution function to annual maximum or annual minimum data.

The spread of the 95% confidence intervals depends on the variability of the source data and the length of the series used. For more extreme annual exceedance probability levels, the 95% confidence interval increases and should always be used in the application of these values.