The eastern Massachusetts shoreline, historically, has experienced many major high impact coastal flood episodes. These major events have produced widespread damage from combined large seas and observed storm tides exceeding area flood elevations by several feet. Examples include the Blizzard of 1978 and the Halloween (Perfect) Storm of October 1991. However, there is a family of coastal flood events which produce moderate coastal flooding, defined by impact, which results in some structural damage to homes, coastal roadways and sea walls. This family of moderate events, by their nature, does not produce flooding from observed storm tides exceeding area flood elevations, but instead produces coastal flooding from storm tides approaching flood elevations combined with large wind driven seas.

This paper will present results from a study on this family of moderate coastal flood events, from 1986 through 2003. The study will examine the combined components of sustained onshore winds including gusts, storm tides, and wave heights as observed from the Boston Buoy (44013) located 16 miles offshore, which together determine the point at which moderate coastal flooding can be expected to commence.