Massachusetts has a glacial coast — sand and clay bluffs the ocean is steadily cutting back. The outer Cape's scarps retreat about 2.6 ft a year on the long-term average, and Nantucket's 'Sconset bluff has lost more than 100 ft since 1990. Here is the measured record, from the state's own transect survey.
Rates come from the Massachusetts Office of Coastal Zone Management Shoreline Change Project (USGS Open-File Report 2012-1189, 2013 update) and the USGS National Assessment of Shoreline Change for New England (Open-File Report 2010-1118/1119, Hapke et al.). Massachusetts has no single statewide "X ft/yr" figure — the rate is computed transect by transect, and swings from accretion to several feet a year of loss along one town. For the exact long-term rate and base flood elevation at one parcel, see the address certificate.
How fast is Cape Cod eroding?
The outer Cape's ocean bluffs retreat about 0.8 m/yr (~2.6 ft/yr) on the long-term average, climbing from roughly 0.5 m/yr at the north end to about 1.0 m/yr toward the south — and short-term rates at individual sites run higher.
Does Massachusetts measure shoreline change?
Yes — the MA CZM Shoreline Change Project, begun in 1989, computes DSAS rates at 26,510 transects spaced 40 m apart, from 1800s surveys through 2009 (USGS OFR 2012-1189).
Is sea level rising on the Massachusetts coast?
Yes — NOAA's Boston gauge shows +2.97 mm/yr relative rise (1921–2024) and Woods Hole +3.13 mm/yr (1932–2024), about a foot per century including land subsidence.
Where is coastal erosion worst in Massachusetts?
Nantucket's Siasconset ('Sconset) bluff is among the worst — more than 100 ft of loss between 1990 and 2014 (over 4 ft/yr), which forced Sankaty Head Light about 400 ft inland in 2007.
What FEMA flood zone is the Cape Cod oceanfront in?
Much of the ocean-facing shore is mapped Zone VE (coastal high-hazard, waves ≥3 ft), with Zone AE and the Coastal A / LiMWA area behind it — confirm any parcel on FEMA's National Flood Hazard Layer.
Cape Cod and the Islands are what the last ice sheet left behind — unconsolidated sand and clay with no bedrock to hold the line. The ocean reworks that sediment south and west, and where it meets a bluff it simply cuts in. The state has been measuring the retreat for decades.
This page is the Massachusetts overview. The $99 Psammite certificate reads your exact address: the long-term erosion rate at your parcel, your storm-surge and FEMA exposure, the uncertainty band, and whether a licensed site review is warranted — built from the same USGS, NOAA and FEMA record.