Empire, LA Coastal Erosion Rate
What USGS measures 11.6 miles southwest of Empire, LA
USGS's shoreline-change data puts this stretch, 11.6 miles southwest of Empire, LA, at 5.31 feet of erosion a year on average, a long-term rate for this specific ~3.5-mile section, not one storm's damage. At that rate, the shoreline has lost roughly 53.1 feet over the last decade.
What "Empire" means on this page
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 Empire, LA, rather than showing one arbitrary line. Segment center: 29.33, -89.75. The survey behind it runs to 2001, in USGS's Gulf of Mexico assessment, using the LRR method. Shoreline surveys aren't repeated every year, so this is the most recent long-term measurement USGS has published for this coast, not a live reading.
What 5.31 ft/yr means over time
Run 11.6 miles southwest of Empire, LA's 5.31 ft/yr rate forward 25 years and it implies about 133 feet of further retreat, assuming nothing changes, which is exactly the assumption a seawall or nourishment project exists to break.
How solid is this number
This reading comes from 78 individual transects averaged together, 100% of which measured erosion rather than growth. USGS's confidence interval here is ±0.97 ft/yr. This segment ranks 50 of 1211 measured US coastal segments, ordered from fastest erosion to fastest growth. Source: USGS Open-File Report 2004-1089. Nantucket, MA sits at national rank 139 for erosion (1.95 ft/yr), one reference point among the 1211 scored segments, 1383 miles from here. Port Sulphur, LA, 2.7 miles off, is the adjacent measured stretch, reading severe erosion at 8.84 ft/yr.
Not this whole stretch, just Empire itself: the Coastal Change Hazards Portal is USGS's own live version of this data.