Mastic Beach, NY Coastal Erosion Rate
Is the coast eroding 2 miles south of Mastic Beach, NY?
0.55 feet a year: that is the measured retreat rate USGS's transects show for the coast 2 miles south of Mastic Beach, NY, averaged across the full historical record surveyed here. At that rate, the shoreline has lost roughly 5.5 feet over the last decade.
The grain of this number
Nothing here is parcel-level. USGS's raw transects run every few hundred feet along the shore; this page averages the ones nearest Mastic Beach, NY into one ~3.5-mile reading rather than picking a single arbitrary line to represent the area. Centered near 40.74°N, 72.85°W. USGS's New England / Mid-Atlantic assessment last surveyed this stretch through 2007-2009, computing the rate with its LRR method. Other US regions were surveyed in different years, sometimes decades apart, so this page states its own rather than implying one national vintage.
25 years at this rate
If 0.55 ft/yr holds for the next 25 years, the coast 2 miles south of Mastic Beach, NY would retreat roughly 14 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 92 individual transects averaged together, 100% of which measured erosion rather than growth. Uncertainty on this specific number: 0.2 ft/yr either side. Sorted from fastest erosion to fastest growth across all 1211 measured segments nationally, this one lands at 285. Source: USGS Open-File Report 2010-1119. For scale: North Eastham, MA, 169 miles away, ranks 200 of 1211 nationally for erosion, 0.97 ft/yr, 1.8x this stretch's rate. 1.9 miles away, Bellport, NY is the nearest other measured stretch: slight erosion at 0.56 ft/yr.
Mastic Beach, NY on the source map: try the Coastal Change Hazards Portal, zoomable well past this page's ~3.5-mile grain.