Tyndall AFB, FL Coastal Erosion Rate
What USGS measures 3.9 miles west of Tyndall AFB, FL
3.9 miles west of Tyndall AFB, FL: USGS's transects didn't pick up a trend here that beats the survey's own uncertainty. That's the majority case nationally, and for this stretch specifically it means the coast is holding, not that the data failed to find anything.
What this reading actually covers
This is a roughly 3.5-mile stretch of coast, not one address or parcel - USGS's own transects run every few hundred feet, but that's finer than any one property needs, so this page reports the stretch nearest Tyndall AFB, FL. Centered near 30.11°N, 85.66°W. USGS's Gulf of Mexico assessment last surveyed this stretch through 2001, 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.
What backs this reading up
This reading comes from 43 individual transects averaged together, 100% of which measured erosion rather than growth. The published margin on this reading runs ±3.71 ft/yr. Taken at face value, this segment's raw -3.57 ft/yr reading would land it 80 of 1211 nationally - a number worth ignoring, since it's statistical noise rather than a real trend. Source: USGS Open-File Report 2004-1089. Rank 1029 nationally for growth belongs to Dillon Beach, CA, 2188 miles from this stretch, measured at 0.53 ft/yr. 1.6 miles away, Lower Grand Lagoon, FL is the nearest other measured stretch: moderate erosion at 2.56 ft/yr.
Not this whole stretch, just Tyndall AFB itself: the Coastal Change Hazards Portal is USGS's own live version of this data.