Hurlburt Field, FL Coastal Erosion Rate
Is the coast eroding 4.9 miles west of Hurlburt Field, FL?
Good news, and an honest one: USGS's data can't distinguish this stretch, 4.9 miles west of Hurlburt Field, FL, from a flat trend. Whatever small movement it measured here is statistical noise, not a reliable direction, so none is claimed.
What this reading actually covers
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 Hurlburt Field, FL, rather than showing one arbitrary line. Segment center: 30.41, -86.80. 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 backs this reading up
This reading comes from 96 individual transects averaged together, 97% of which measured erosion rather than growth. The published margin on this reading runs ±0.4 ft/yr. The unadjusted figure here, -0.2 ft/yr, would place it 501 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 Open-File Report 2004-1089. For scale: Brigantine, NJ, 936 miles away, ranks 1166 of 1211 nationally for growth, 2.23 ft/yr. Navarre, FL, 3 miles off, is the adjacent measured stretch, itself no significant trend.
Not this whole stretch, just Hurlburt Field itself: the Coastal Change Hazards Portal is USGS's own live version of this data.