(LACK OF) IMPACT OF HURRICANE MICHELLE ON TIDAL FLATS, ANDROS ISLAND, BAHAMAS

Tidal flats and shorelines represent dynamic geomorphic and sedimentologic systems that respond to a number of forcing mechanisms. Most studies of modern carbonate tidal flats suggest that storms are the most significant mechanism influencing sedimentation. The purpose of this study was to evaluate the impact of Hurricane Michelle (November 6, 2001) on the tidal flats of Andros Island, Bahamas. Data include eight 11 x 11 km remote sensing Ikonos images (1 m resolution panchromatic and 4 m resolution multispectral) from four different areas. One set of four images was acquired in early summer 2001, before Hurricane Michelle; the other set was acquired winter 2001/2002, after Hurricane Michelle.

Remote sensing data, validated by field observations, demonstrate that Hurricane Michelle had little impact on the tidal flats, even though it still had hurricane force as it passed. Several factors appear to have combined to minimize the storm’s impact on both sedimentation and erosion: low level of water on the bank resulting from ebb tides and, in the northwestern area, from offshore storm winds; the short duration of the storm resulting from high forward velocity; and, in the southwestern area, the orientation of Hurricane Michelle relative to the shoreline. These results illustrate the variability and interaction of many variables that impact tidal-flat sedimentation and erosion.

Understanding the dynamics of tidal-flat sedimentation will require continued monitoring and assessment of low-impact storms such as Michelle, as well more glamorous hurricanes that produce wide-spread death, destruction, and deposition.