Los Osos, CA Coastal Erosion Rate
Is the coast eroding 4.5 miles southwest of Los Osos, CA?
Good news, and an honest one: USGS's data can't distinguish this stretch, 4.5 miles southwest of Los Osos, CA, from a flat trend. Whatever small movement it measured here is statistical noise, not a reliable direction, so none is claimed.
The grain of this number
USGS surveys the coast in transects spaced a few hundred feet apart; this page groups the nearest ones into a single ~3.5-mile reading for the stretch closest to Los Osos, CA, rather than showing one arbitrary line. Segment center: 35.27, -120.89. USGS's California assessment last surveyed this stretch through 1852-2016, 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.
How solid is this number
Averaging 7 separate transects produced this segment's rate, with 0% individually reading as erosion, rather than relying on any single survey line. USGS's confidence interval here is ±0.24 ft/yr. The unadjusted figure here, 0.09 ft/yr, would place it 847 of 1211 if ranked directly - but an unreliable rank isn't a useful one, which is exactly why "no significant trend" is the headline instead. Source: USGS National Shoreline Change data release (ScienceBase, DOI 10.5066/P94J0K7Z), Kratzmann 2024 / Data Report 1187. For scale: North Wildwood, NJ, 2524 miles away, ranks 1193 of 1211 nationally for growth, 4.21 ft/yr. 2 miles up the coast, Los Osos, CA shows the same lack of a significant trend.
Not this whole stretch, just Los Osos itself: the Coastal Change Hazards Portal is USGS's own live version of this data.