curtadams wrote:
The forecast said "up to 28 feet". That implies no more. Most people have to rely on authoritative forecasters to give predictions - you can't expect everyone to develop the skills of even a semi-professional forecaster. As to Camille, how can you fault people figuring Katrina, a Cat 4, wouldn't be worse than Camille, which has always been held up as the example of the worst a US hurricane ever gets? People *have* to make decisions on when to evacuate and when not to, because you can't evacuate for every TS in the Atlantic, and most have no choice but to rely on the NHC and analogous institutions for information on that decision.
In any case, my point is that the forecast did cost lives. Had the NHC correctly forecast "SURGE APPROACHING 40 FEET POSSIBLE, FAR EXCEEDING CAMILLE" there would have been few deaths in MS and certainly not 200+. Since the scale of the surge surprised everybody, I'm not knocking their forecasting. But a more accurate forecast would have saved at least 200 lives.
A subtlety on the NHC forecast is that they effectively pad the wind speeds. The "surface wind" is defined as 10 meters up over open ocean. On land, with more resistance, and on the 1st or 2nd story, it will be considerably less. So people rarely experience even the forecast winds. My impression of surge forecasts is that they are padded too, although I can't cite anything to prove that. Note the "up to" teminology - warns people to be ready for it but can't be dinged if surge falls noticeably short. Small pads are, after all, an excellent way to handle uncertainty. IMO what's happening is that all the ex-Cat 5 storms have come in with such a surge it blew the NHC's pad.
Dear Lord, where do I begin???
1) Curt, how do you know the storm surge level was 30, 35, or 40 feet?? Are you a surveyer with NOAA or the US Army Corps of Engineers? Have you been to Waveland or Bay St Louis, MS since Katrina's landfall (I haven't yet, but plan to travel to the Mississippi coast in a few days to conduct own storm survey).
FACT: no one knows yet what the true storm surge height was in the Waveland area. At Gulfport harbor, it was 26' feet.....it may or MAY NOT have exceeded 28' feet in some areas. It also may have been a 26-28' storm surge with 10' "wind waves" on top.....which produces a water level of 35'+.
2) Even IF the true storm surge level was over 28' feet.....remember what I stated above? STATE OF THE ART!!! How in the devil can NHC forecast a storm surge of "UP TO 40 FEET"....when NO model data and NO past known hurricanes of similar intensity have produced a storm surge above 25'? Are they (NHC) supposed to be mindreaders or psychics? Let me tell you something friend.....when it comes to hurricanes, I'm about as knowledgeable as you'll find online, and I had no idea a 30'+ surge was possible in that area......not in a 927 mb hurricane. Again I repeat what I stated above. STATE OF THE ART......STATE OF THE ART. You can only forecast based on the data available.
3) Your claims that NHC "pads" a hurricane's sustained wind speeds is an OUT AND OUT FALSEHOOD!! It's completely false; a complete and utter falsehood. NHC IMO is too conservative in their intensity estimates; if anything, their estimates are TOO LOW. If they had padded Katrina at Mississippi landfall, they'd have advised an intensity of 150-155 mph......that's the pressure/relationship of a 927 mb hurricane. They only estimated sustained winds of 125-130 mph.....which again IMO is too LOW. I heard all the stories about hurricane Dennis "falling apart" before landfall....and after seeing the aftermath in person, the sustained winds IMO were at least 125-130 mph west of Navarre Beach.......not the 120 mph estimated by NHC in their landfall advisory.
Here's some good advice: don't post about something UNLESS you know what the heck you are posting about......because I DO KNOW what I'm posting about.
PW