Hurricane Ivan -- Thursday 9/16 thread [Landfall!]

Hurricane Ivan Advisory Number 55

Statement as of 10:00 PM CDT on September 15, 2004

...Extremely dangerous Hurricane Ivan coming closer to the northern Gulf Coast...strong winds already moving onshore...

A Hurricane Warning is in effect from Grand Isle Louisiana to Apalachicola Florida...including the greater New Orleans area and Lake Pontchartrain. A Hurricane Warning means that hurricane conditions are expected within the warning area...generally within the next 24 hours. Preparations to protect life and property should be rushed to completion throughout the entire warning area.

A Hurricane Watch remains in effect from Morgan City Louisiana to west of Grand Isle.

A Tropical Storm Warning remains in effect from Morgan City to west of Grand Isle...and from east of Apalachicola to Yankeetown Florida.

At 10 PM CDT...0300z...the large eye of Hurricane Ivan was centered near latitude 29.3 north... longitude 88.1 west or about 65 miles south of the Alabama coastline.

Ivan is moving slightly east of north near 12 mph...and this motion is expected to continue for the next 24 hours. On the forecast track...the center of the hurricane will reach the coast early on Thursday.

Maximum sustained winds are near 135 mph...with higher gusts. Some fluctuations in intensity are possible prior to landfall...but Ivan is expected to make landfall as a major hurricane...category three or higher. Occupants of high-rise buildings within the Hurricane Warning area can expect higher winds than those experienced at the surface...about one Saffir-Simpson category higher at the top of a 30-story building. After landfall... hurricane force winds could spread inland up to about 150 miles near the path of the center.

People are strongly advised not to venture out from shelter during the calm conditions of the eye...as winds will increase rapidly with little or no warning when the eye passes.

Hurricane force winds extend outward up to 105 miles from the center...and tropical storm force winds extend outward up to 290 miles. The Dauphin Island C-man station reported sustained winds of 54 mph with a gust to 83 mph...and Pensacola Naval Air Station reported sustained winds of 51 mph with a gust to 68 mph.

The latest minimum central pressure measured by a NOAA hurricane hunter aircraft was 933 mb...27.55 inches.

Coastal storm surge flooding of 10 to 16 feet above normal tide levels...along with large and dangerous battering waves...can be expected near and to the east of where the center makes landfall. Lesser...but still significant surge values will be experienced where onshore flow occurs west of the center.

Dangerous surf conditions...including rip currents...are likely elsewhere along the Florida Gulf Coast.

Rainfall accumulations of 10 to 15 inches...with isolated higher amounts...can be expected in association with Ivan.

Tornadoes are possible over the next 24 hours in southern Alabama... the Florida Panhandle and Big Bend area...and southwestern Georgia.

Repeating the 10 PM CDT position...29.3 N... 88.1 W. Movement toward...north near 12 mph. Maximum sustained winds...135 mph. Minimum central pressure... 933 mb.

For storm information specific to your area...please monitor products issued by your local weather office.

Intermediate advisories will be issued by the National Hurricane Center at midnight CDT and 2 am CDT followed by the next complete advisory at 4 am CDT.

Forecaster Pasch

$$

Yeah. It's going to be a real soggy few days for both of us.

To show you how crazy those five-day hurricane guesstimates are...at 11:00 EDT last night, the NHC 120-hour track had Jeanne parked directly over Hilton Head. Six hours later, at 120 hours, now they're saying she'll be at least 100 miles east of Jacksonville westbound for St. Augustine.

I almost wish they'd go back to issuing just three-day maps and skip the five-days...or just put a blob out after 72 hours, without a center track line. I know they tell us "look at the cone, not at the line," but it's human nature to look at that track line and think it's authoritative. And when that track line can wobble 200 miles in a six-hour period (no slam on the NHC/NWS, that's just the best they can do forecasting these things), people are going to get pissed.

Just had a hell of a rainband come through northeast Columbia. 35-40 mph winds and blinding rain for about 20 minutes and it's just started up again. And we're supposed to get these off and on all day, with long periods of no rain in between. Nothing like what the folks on the Gulf just went through, but still not much fun.

}:-)4

It is still too early for official overall damage estimates or details, but there is enough anecdotal information to begin looking for overall patterns. Note that since all this has been filtered through the media, which tends towards the sensationalistic, using it as a baseline or average will skew the damage overview worse than it really is, however, it does indicate what forces certain areas were subject to.

Gulf Breeze, Florida:
One poorly constructed residence, F4 damage (some walls standing, some foundation showing), minimum five separate residential areas totally destroyed (TD, multiple, 3 or more, houses reduced, probably by surge, to flotsam and distributed over a large debris field for each area), Oriole beach, 1 TD area, 1/4 mile debris field blocking access to Bob Sikes bridge (Gulf Breeze to P'cola beach), 30 foot section of Bob Sikes bridge missing, Amsouth Bank partially collapsed, Garcon Point and Pensacola Bay bridges closed pending inspection, known erosion under Pensacola Bay Bridge northern approach.

Pensacola Beach, Florida:
Ft. Pickens mostly flooded, shallow, two or more four story buildings missing 75% roof and 25% top floor, 4 unit condo 50% collapsed, 20+ unit apartment or condo 50% collapsed, 10 unit condo 50% collapsed, 4 story building 75% collapsed, 3 residences east of Dome Home F5 (bare foundation) damage, per sheriff via FOX-80% of residences damaged or destroyed, Naverre Causeway closed, structural damage, access to P'cola Beach by boat only.

Pensacola, Florida:
low lying areas shallow flooding, some surge (wave action) damage, but more water damage, comm. building roof collpase, area with multiple F3 (some major walls missing, most standing, roof missing)damage to residences, 3 partially collapsed commercial bldgs, 1 partially collapsed residence, 1 TD area, westside waterfront homes flooded to 4 feet, I-10 Escambia Bridge 30 foot section of eastbound deck missing, two eastbound piers possibly missing, westbound decks detached on both sides of the channel span, piers appear to be intact, the two westbound lanes may see bi-directional service prior to restoration of eastbound lanes, Highway 90 bridge over Escambra river closed, some reports indicate damage, some reports indicate debris only.

Grande Lagoon, Florida:
Reported surge to 26 feet, 12 residences F5 (bare foundation) damage, 2 fatalities reported.

Perdido Key:
No information available.

Navarre, Florida:
Condo partially collpased, Navarre Beach causeway closed, subdivision on Thresher road partially sumberged, "every convenience store from Navarre to Gulf Breeze damaged", large sections of highway 87 underwater.

Pensacola Naval Air Station:
No information available.

Gulf Shores, Alabama:
At least one cross island breach, 20 to 30' wide, main highway cut with scouring 6 to 8 feet deep, two or more half mile or greater ressidential/commercial sections still underwater, both involving the main highway, 3 story building 25% collapsed, at least two TD areas.

Orange Beach, Alabama:
2 5(+) story condo highrises 25% collapsed, F4 damage to multiple buildings, 2 20 unit condos 75% collpased.

Foley, Alabama:
Dollar General comm. building 90% collapsed.

Overall, low lying areas from Gulf Shores Alabama to Navarre, Florida, subject to storm surge suffered significant damage, while wind damage appears to have been much lighter, primarily damaging trees, power lines, roofs, windows and doors, and light commercial buildings. Wind damage largely appears to be at F2 (significant roof damage) levels or below.

Relief efforts have been hampered by bridge damage, but currently 2000+ National Guard troops are enroute or arriving via Highway 89/29. essentially blocking that route to non-relief traffic. It seems likely that significant water shortages due to transportation difficulties can be expected over the next few days.

If it was my bridge and my city, I'd lay wide flange shallow H beams across the missing pier on the westbound lanes, up to one inch shy of the existing road surface, plate them with bolted steel deck plates and get the inbound side open while I put a permanent fix in for the eastbound lanes.

After the eastbound lanes were open, I could go back and get the job redone right on the westbound lanes.

If the span is too great for the H beam stringers to carry the expected loads, you could cantilever the stringer beams back a couple piers on each side of the gap, break them over the pier edge closest to the missing section, hang a massive steel plate off the ends of the stringers, then use whatever depth I Beams you need to carry the load across the double span.

The stringer/plate/I beam attachments would all be in shear, capable of carrying significant loads.

Matter of fact, you could use that method for a permanent fix, provided the remaining piers adjacent to the gap are capable of supporting the point loads at either end of the long span.

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