Edgartown, MA Coastal Erosion Rate
Is the coast eroding 4.8 miles southwest of Edgartown, MA?
The coast 4.8 miles southwest of Edgartown, MA has been retreating at a measured 2.13 feet a year, USGS's own long-term rate for this stretch, built from historical shoreline positions rather than a single survey. At that rate, the shoreline has lost roughly 21.3 feet over the last decade.
The grain of this number
This is a roughly 3.5-mile stretch of coast, not one address or parcel - USGS's own transects run every few hundred feet, but that's finer than any one property needs, so this page reports the stretch nearest Edgartown, MA. Centered near 41.35°N, 70.60°W. Survey years: 2007-2009, method LRR, from USGS's New England / Mid-Atlantic shoreline-change assessment. That's how current the data is here, real, but not a live feed, since a shoreline survey is a major undertaking, not an annual check-in.
25 years at this rate
If 2.13 ft/yr holds for the next 25 years, the coast 4.8 miles southwest of Edgartown, MA would retreat roughly 53 more feet, a projection, not a certainty: erosion rates shift with storms, sediment supply and any armoring built in the meantime.
Where this fits nationally
This reading comes from 82 individual transects averaged together, 100% of which measured erosion rather than growth. The published margin on this reading runs ±0.52 ft/yr. Sorted from fastest erosion to fastest growth across all 1211 measured segments nationally, this one lands at 127. Source: USGS Open-File Report 2010-1119. Colma, CA sits at national rank 304 for erosion (0.48 ft/yr), one reference point among the 1211 scored segments, 2737 miles from here. 2.6 miles up the coast, Edgartown, MA shows 2.21 ft/yr of eroding.
Not this whole stretch, just Edgartown itself: the Coastal Change Hazards Portal is USGS's own live version of this data.