Sand City, CA Coastal Erosion Rate
What USGS measures 0.9 miles southwest of Sand City, CA
0.42 feet a year: that is the measured retreat rate USGS's transects show for the coast 0.9 miles southwest of Sand City, CA, averaged across the full historical record surveyed here. At that rate, the shoreline has lost roughly 4.2 feet over the last decade.
What this reading actually covers
Nothing here is parcel-level. USGS's raw transects run every few hundred feet along the shore; this page averages the ones nearest Sand City, CA into one ~3.5-mile reading rather than picking a single arbitrary line to represent the area. Centered near 36.61°N, 121.86°W. Survey years: 1852-2016, method LRR, from USGS's California 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 0.42 ft/yr holds for the next 25 years, the coast 0.9 miles southwest of Sand City, CA would retreat roughly 11 more feet, a projection, not a certainty: erosion rates shift with storms, sediment supply and any armoring built in the meantime.
How solid is this number
73 transects feed this segment's number; 100% of them individually measured retreat. The published margin on this reading runs ±0.2 ft/yr. This segment ranks 342 of 1211 measured US coastal segments, ordered from fastest erosion to fastest growth. Source: USGS National Shoreline Change data release (ScienceBase, DOI 10.5066/P94J0K7Z), Kratzmann 2024 / Data Report 1187. Rank 472 nationally for erosion belongs to Point Arena, CA, 187 miles from this stretch, measured at 0.23 ft/yr, 0.5x this stretch's rate. 1.6 miles up the coast, Monterey, CA shows the same lack of a significant trend.
Not this whole stretch, just Sand City itself: the Coastal Change Hazards Portal is USGS's own live version of this data.