Coastal profile evolution at Duck, North Carolina: A cautionary note

The Hurst exponents of 10.8-year-long time series of cumulative bed level observed between the shoreline and similar to 8-m water depth on an ocean beach are shown to be consistent with bed-level time series described by a sinusoid with a 10.8-year period plus white noise. Thus, for these observations, Hurst exponents cannot distinguish self-organized morphological evolution from the hypothesis that nearshore morphology on monthly to decadal timescales is a forced response to small-scale physical processes driven by waves and currents.