Annual exceedance probability levels, displayed in meters or feet, relative to tidal datums and the geodetic North American Vertical Datum (NAVD88), if available. On the left, exceedance probability levels for the mid-year of the National Tidal Datum Epoch (1983-2001) Mean Sea Level (MSL) datum, currently in effect at most stations, are displayed. For stations with rapid sea level rates, such as those in Louisiana, Texas, and Alaska, a 5-year modified epoch MSL datum is used. On the right, projected exceedance probability levels and tidal datums, assuming continuation of the historical linear trend, are displayed. See the Annual Exceedance Probability tab for 95% confidence intervals for each of the exceedance probability levels shown here.