Graham and Diaz (2001; to appear Bull. Am. Met. Soc.) and Graham et al. (2001; in prep.) document major upward trends the intensity of North Pacific winter cyclones since 1950 and associated changes in the wave climate of the Northeast Pacific. These changes in wave climate, evaluated with a state-of-the-art wave model driven with NCEP/NCAR reanalysis winds, include dramatic increases in extreme and average wave heights, changes in favored incident direction, and increases in wave period. Along the coast of North America these trends towards increasing extreme wave heights have been largest in southern California and northern Baja California and decrease slowly to the north. This pattern is related to the tendency for more intense cyclones and a southward migration of the storm track.

The coastal impacts of these changes have been have been particularly pronounced at inshore sites in the Southern California Bight where the combined effects of increasing deep-water wave height and changes in preferred approach direction each contribute to increasing inshore waves. The magnitude of these changes is substantial - for example, at some inshore sites the estimated 100-year extreme wave over the period 1948-75 becomes has an estimated 1-year return period for from 1976-97. These changes in wave climate have profound implications for coastal structures and structure design, sediment transport, and beach erosion. Initial results from sediment transport modeling for a section of beach near San Diego show major increases potential sediment transport rates and sediment divergence. These simulated changes are likely related to major problems with bluff erosion in the region.