Pulling out the advisory surge numbers to compare to Apalachee Bay geography. NHC Advisory 14 lists Carrabelle to Suwannee River at 15-20 ft, Apalachicola to Carrabelle at 10-15 ft, and Suwannee River to Chassahowitzka at 10-15 ft. This is catastrophic territory for low-lying Big Bend communities. The bay is extremely shallow and broad, which is exactly the geometry that amplifies surge.
Storm surge forecast for Apalachee Bay — how bad?
Keaton Beach and Steinhatchee are both in the Suwannee River zone. 10-15 ft of surge in those communities will be devastating — the land is barely above sea level. The Tampa Bay zone (5-8 ft) is bad but the Big Bend numbers are the most extreme I've ever seen on an advisory. NHC emphasized the deepest water will be near and east of the landfall location.
For reference, the advisory also lists Indian Pass to Apalachicola at 6-10 ft and Chassahowitzka to Anclote River at 8-12 ft. Even the Charlotte Harbor area is seeing 3-5 ft. This surge footprint is enormous. NHC called the surge 'catastrophic and deadly' in the key messages — that phrasing doesn't come out lightly.
From an emergency-management standpoint: when NHC says 'your opportunity to evacuate is almost over,' that's the moment to act. Rescue crews cannot operate in 20-ft surge. Once the water comes in you are on your own until conditions allow re-entry. Do not underestimate the Suwannee River to Carrabelle corridor numbers.