What is everyone's worst case hurricane scenario? (Ortt pg3)

[Ixolib]

Worst case is any storm hitting anywhere where the surge is the overwhelming factor.

Both short- and long-term impacts of wind damage are significantly less than short- and long-term impacts of surge damage. So, if a Cat 5 strikes a coastline that has limited susceptibility to surge, the "worst case" will not exist. However, if the same Cat 5 strikes a coastline with a HIGH susceptibility to surge, the "worst case" will be clearly evident......

[Opal storm]

Worst case is any storm hitting anywhere where the surge is the overwhelming factor.

Both short- and long-term impacts of wind damage are significantly less than short- and long-term impacts of surge damage. So, if a Cat 5 strikes a coastline that has limited susceptibility to surge, the "worst case" will not exist. However, if the same Cat 5 strikes a coastline with a HIGH susceptibility to surge, the "worst case" will be clearly evident......

I disagree,wind can definitely be a worse case scenario for people.Andrew and Charley proved that wind can cause just as much devastation as surge.

[Ixolib]

Worst case is any storm hitting anywhere where the surge is the overwhelming factor.

Both short- and long-term impacts of wind damage are significantly less than short- and long-term impacts of surge damage. So, if a Cat 5 strikes a coastline that has limited susceptibility to surge, the "worst case" will not exist. However, if the same Cat 5 strikes a coastline with a HIGH susceptibility to surge, the "worst case" will be clearly evident......

I disagree,wind can definitely be a worse case scenario for people.Andrew and Charley proved that wind can cause just as much devastation as surge.

In clarification to my point, a large part of the damage with Andrew was due to poor/shoddy construction. Had many of those homes been built to stronger standards in the first place, the results with Andrew would have been far less. As for Charley, I agree that the impact was great. But again, much of the damage there was to manufactured homes, sheet-steel sided marine facilities, gas station roofs, and other commercial buildings with relatively low resistance to wind. Charley's impact on conventionally constructed homes and other buildings with a full and solid foundation was - I believe - neglagible.

Of course, I suppose anyone could use a similar argument for surge - i.e., IF no one built homes below 40 feet above sea level and IF New Orleans wasn't almost entirely below sea level, the impact of Katrina would barely have even been newsworthy...............

[Derek Ortt]

Andrew's damage was NOT poor construction.

That was based upon the incorrect assessment of Andrew's intensity. Andrew's damage was due to wind gusts equal to those in the Xenia Tornado (about 200 mph based upon structural analyses in Xenia). Winds at that intensity will level most anything.

It is worth noting that the last 3 cat 4 or 5 hurricanes to hit the USA (Andrew, Iniki, and Charley) were wind events. This is despite Andrew producing a 17 foot surge, and about 10 feet in Coconut Grove. That is because hurricanes of that severe intensity are basically extended violent tornadoes, with gusts approaching those in the strongest of tornadoes

[Derek Ortt]

Charley's impact on conventionally constructed homes and other buildings with a full and solid foundation was - I believe - neglagible

Re-enforced concrete structures were destroyed in Charley. It depended if those miniswirls discovered by Dr Fujita in Andrew hit the structure or not. Like in Andrew, Charley's damage was in streaks

[Aquawind]

It depended if those miniswirls discovered by Dr Fujita in Andrew hit the structure or not. Like in Andrew, Charley's damage was in streaks

That is a great point and something many people don't understand..just how violent those can be. Combined with sustained winds and heavy rains pretty much anything can be destroyed. Yes I saw a few pictures of concrete block buildings in piles from wind alone..no surge. Charlie was dang near microscopic in size..

[Derek Ortt]

those streaks are why I would not fault anyone from evacuating if they are outside of a surge zone, but in the likely cat 4/5 wind range. It's basically a 50/50 chance that you will be in or out of one of those streaks.

If a person knew 24 hours in advance that there was a good chance that an EF4 or EF5 tornado would hit their property... chances are they would not remain. A cat 4 or 5 hurricane basically is that

[Aslkahuna]

If I recall correctly, the first really documented case of wind streaks in the windfield of an intense hurricane was with Hurricane Celia which hit Corpus Christi TX in 1970. That was very close to a worse case scenario since the storm underwent strong intensification in the final hours before landfall.

Steve

[Ptarmigan]

If I recall correctly, the first really documented case of wind streaks in the windfield of an intense hurricane was with Hurricane Celia which hit Corpus Christi TX in 1970. That was very close to a worse case scenario since the storm underwent strong intensification in the final hours before landfall.

Steve

Hurricane Celia had sustained winds of 130 mph and gusts as high as 180 mph, which is the highest measured in Texas. Celia was also a small hurricane, which would be one reason it intensified quickly.

[Ptarmigan]

The worst case is a large and powerful hurricane that is about to hit a densely and heavily populated area. The winds are of Category 5 and it is a large hurricane and produces massive storm surge. It could be New York, Miami, Jacksonville, New Orleans, and Houston.

[CrazyC83]

My worst case scenario:

Tropical depression develops just east of Hispaniola and moves extremely slowly. It barely becomes a tropical storm, but the heavy rains in Haiti and the Dominican Republic are devastating.

The storm then takes a track similar to Jeanne, but gets blocked by the Bermuda High which strengthens and pushes the storm west. The warm water allows it to strengthen gradually, becoming a hurricane before the loop and Category 2 after. It strengthens into a Category 3 as it approaches the Bahamas and remains there due to eyewall cycles.

Then, as it clears the Bahamas, shear decreases and the storm strengthens rapidly in the Gulf Stream approaching South Florida. It strengthens from 115 to 175 mph within 12 hours, and remains there until landfall over Key Biscayne as it begins to move northwest. The strongest winds are over downtown Miami, and it quickly turns north as the ridge retreats somewhat, moving at about 15-20 mph.

The storm remains very intense as it begins to accelerate to the north-northeast, in the middle of the Peninsula. It remains a Category 3 hurricane to near Orlando and a Category 2 hurricane with 100 mph winds as it exits near Flagler Beach. The warm Gulf Stream restrengthens the storm, and it becomes a Category 3 again, as it makes another landfall over the Outer Banks with 125 mph winds.

Moving fast, the storm is pushed northward due to a redevelopment of the Bermuda high, and it makes landfall near Manasquan, NJ with 115 mph winds. It is moving very fast and pushes the storm surge into northern New Jersey, Long Island, New York City and southern New England, with wind damage well inland as it weakens.

[tailgater]

IMHO It's still the Miss/ SE La. region getting hit by a INTENSTIFING CAT 4 or larger moving slowly in a more WNW motion just south of New Orleans essentually flooding the rest of the New Orleans, Gretna, Metairie,Kenner, Laplace, Houma, Slidell and lots of the North Shore.
I-10, Hwy 11, Causeway, I-55, and the I-10 east of Laplace would all probably be impassible, flood waters could reach as far NW as East Baton Rouge Parish. (see slosh models for this region). That would make it very difficult to get aide to this area. Also Most of the refineries in area would be down for sometime.
Not a very likely scenario, much like NYC getting hit with a Cat 3 or 4, which would probably worst yet.

Could someone tell me if any studies have been made on difference on Intensifying storms making landfall vs weaking ones. I would think that it would be a big difference in wind damage and a much less difference in surge and I'm not sure on rainfall.

[CrazyC83]

IMHO It's still the Miss/ SE La. region getting hit by a INTENSTIFING CAT 4 or larger moving slowly in a more WNW motion just south of New Orleans essentually flooding the rest of the New Orleans, Gretna, Metairie,Kenner, Laplace, Houma, Slidell and lots of the North Shore.
I-10, Hwy 11, Causeway, I-55, and the I-10 east of Laplace would all probably be impassible, flood waters could reach as far NW as East Baton Rouge Parish. (see slosh models for this region). That would make it very difficult to get aide to this area. Also Most of the refineries in area would be down for sometime.
Not a very likely scenario, much like NYC getting hit with a Cat 3 or 4, which would probably worst yet.

Could someone tell me if any studies have been made on difference on Intensifying storms making landfall vs weaking ones. I would think that it would be a big difference in wind damage and a much less difference in surge and I'm not sure on rainfall.

Such an intensifying storm would create a Cat 1-2 storm surge. Look at Charley for an example of such. Also I can't see a storm intensifying while stationary on the coast; land interaction and the shelf waters would prevent such. Such would need to be a very small storm to intensify near the coast. It would be more of a wind event than anything.

To be worse than Katrina at the same intensity, it would have to be even larger (in physical size) and have to approach from the SE to drain the maximum storm surge into Lake Pontchartrain while still flooding the Mississippi coast.

[Derek Ortt]

it does not matter if a storm is intensifying or weakening regarding the surge. People really need to comprehend that point.

What matters is the size of the wind field. Charley produced no surge because it was very small. Slosh simulations showed that had Charley have been at Andrew's size, it would have produced about 15 feet of surge

[johnq1954]

those streaks are why I would not fault anyone from evacuating if they are outside of a surge zone, but in the likely cat 4/5 wind range. It's basically a 50/50 chance that you will be in or out of one of those streaks.

Problem is - predictions of intensity aren't very good.

I was sitting in Tampa when they were forecasting Charley as a Cat 2 that would directly hit us. Had it been forecasted as a Cat 4, I would have evacuated the city. When the weather guys on TV said it had intensified to a Cat 4 west of Naples, there was a collective 'oh crap' uttered all over the city.

Then it turned and leveled Captiva and Punta Gorda, and smashed its way to Daytona Beach.

Had Charley come up Tampa Bay as a Cat 4, there would have been hundreds killed by the surge alone, let alone the 'streaks'.

[Derek Ortt]

I don't think there would have been a significant surge had the same Charley hit Tampa. Charlotte Harbor is just as surge prone, yet, the surge was lower than TS Gabrielle in 2001 due to the small size.

Now the streaks... well... thats a differnt story in Tampa, especially due to the high rises. The winds would have caused many deaths

[Derek Ortt]

As I suspected, nobody even came close to what I was thinking as to the worst case

Here is my worst case (after about a week of soliciting other's worst cases)

Delta, a little larger, a little stronger, more tropical, moving at speeds comparable to those of Nicole and Vince when they formed near the Canary Island producing a few feet of rain at LA PALMA. To top it off, less than a weak after a volcanic eruption at LA PALMA makes the island very prone to severe landslides.

Totally unexpected. Not sure that this scenario can ever occur (if it does, I won't have to face criticism for that statement); however,the point is it does illustrate the true worst case, which I put below in bold caps

THE WORST CASE IS THE UNEXPECTED. ALWAYS EXPECTED THE UNEXPECTED TO OCCUR TO AVOID THIS WORST CASE

[Windspeed]

To top it off, less than a weak after a volcanic eruption at LA PALMA makes the island very prone to severe landslides.

Totally unexpected. Not sure that this scenario can ever occur (if it does, I won't have to face criticism for that statement)

I am sure you would rather face the criticism than have your scenario unfold: structural failure of La Puma's western facing slope, massive landslide and mega-tsunami potentially devastating the eastern seaboard of the North America, Bahamas and Caribbean. Geological evidence supports that mega-tsunamis have been produced by failed dikes within the internal edifice of Canary's volcanoes in the past. This has also been found to occur at several other volcanic islands around the globe with a similar felsic composition.

This scenario does not necessarily need a stationary tropical storm, or successive occurrence of storms in combination with eruption to take place. Above average rainfall for an extended period of time from multiple mid-latitudinal lows or an active subtropical jet can cause over saturation above the already present internal large reservoirs of water. Also, the most recently active vent at La Puma does not even have to erupt. Only an intrusion of new magma into the edifice in combination with the already known water reservoirs that exist there could potentially force over expansion, old dike failure and resulting structural failure of the volcano's edifice. Porous rock between the old dike system that runs through La Puma are known to trap and hold very large reservoirs of water even during periods of low annual precipitation. As to whether the heavily documented fault that exists through La Puma's edifice is large and deep enough to produce the hypothesized landslide and mega-tsunami is still in debate among the geological community. La Puma may erupt or experience hundreds of active cycles with no major slide; however, with all the attention it has received, I am quite certain everyone will be on extra alert when magma begins to intrude into that edifice again.

You are 100% on target about the unexpected. Even with all the climatological and geological data that has been researched over the past few centuries, the likelihood of a major event occurring when and where we have not foreseen is high. A vulcanologist, Jelle Zeilinga de Boer, once told me that a place like Yellowstone can get all the attention for the scary "mega eruption," but the likely scenario for the next VEI 7 or 8 magnitude event on this planet will occur unexpectedly at not only time but location.

[Derek Ortt]

yeah, Id rather face the criticism for saying that event is very unlikely if it were to ever occur.

Unfortunately, if I am living in Miami then, I won't. Hard to face criticism if I died in the event

[Windspeed]

It is pretty disturbing to try and imagine 100s of millions of people trying to evacuate low-lying areas of a coastal plain in a 3-4 hour period. We can only hope such a horrific scenario never took place in our lifetime. Of course, we have plenty of other disturbing stuff to worry about that is potentially very much in our lifetime. Something as subtle as ground water pollution can be responsible for large loss of life. Conscientious as we may be, we always live under threat. But you cannot live in a constant state of fear, eh? Some things are just beyond our control. So enjoy living in Miami.