how would you revise the SS scale

[docjoe]

bump

I am bumping this because of the ongoing argument regarding "Katrina was or was not this strength, SS is useless, etc". With the 20/20 of hindsight from 2005 how could a scale (ss or otherwise) been used for better and more accurate warning??

docjoe

[wxman57]

The SS scale is good in that it gives the general public at least SOME idea of the potential threat. However, it fails miserably in completely defining the threat. The main failure is the SS scale ranks hurricanes according to one value alone - peak 1-minute winds. And then it assumes that all hurricanes are alike. Well, I can tell you, that all hurricanes are not alike, structurally.

Take a look at two "identical" storms (according to the SS scale). Both Dennis & Ivan struck the Gulf coast in about the same spot as 105 kt / 120 mph hurricanes. However, Ivan was 3 times the size of Dennis at landfall. As such, Ivan produced much more damage.

Don't assume that a hurricane's max wind field extends completely around the center. In many cases, peak winds may be found only in a tiny part of perimiter of the center. You can have a Category 3 hurricane with 100kt winds over 100 square miles, and you can have the "same" Category 3 hurricane with 100kt winds covering over 5000 square miles. Believe, me, the size of the wind fields and the extent of the higher wind speeds is a major factor in the potential destructive force (wind and storm surge).

Katrina was a Cat 3 hurricane at landfall, but hurricane force and greater winds extended much, much farther out than with a typical hurricane. Those high winds built up tremendous waves and an enormous storm surge. It's not the tiny areas of peak winds that build large waves and high surges, it's the expanse of lesser winds fields - something which the SS scale ignores.

[milankovitch]

How about the total kinetic energy of the circulation, then split it in to 5 different catagories. That should keep it simple and not change the familliar 1-5 notation. It won't corrate perfectly with destrucitve potential but its simple and probably correlates better than peak sustained wind.

[MGC]

I could not have said it better wxman57. Compare for instance Hurricane Iris of 2001 and Katrina. Hurricane Iris was a small core Cat-4 hurricane that stuck Belize. Iris' eye was so small that the hurricane hunters had a hard time placing a sonde into the eye. Iris made landfall as a 125KT, 948mb Cat-4 hurricane. Iris had a very tight wind field. Yet, on the SS scale, Iris was a more intense hurricane than Katrina. In terms of damage, Katrina was far more destructive. The SS scale was originally developed to reflect the damage potential of a hurricane. It has failed miserably........MGC

[StormScanWx]

This was posted in the first post of this page:

Hurricane Cornbread

I'm sorry this is off-topic, but....

LOL!

[Extremeweatherguy]

I think I would have 4 storm ratings:

Level 0: Winds weaker than 58mph. No real storm surge.

Level 1: Winds 58-99mph. Minor storm surge likely.

Level 2: Winds 100-150mph. Moderate storm surge likely.

Level 3: Winds over 150mph. Large storm surge likely.

This kind of scale would give people more of an idea of when to stay and when to leave. In a level 0, everyone would be safe a no wind damage is expected. In a level 1 the immediate coast should leave, but those more than a mile inland should stay. In a level 2 everyone within 3 miles of the coast or a major waterway/bay should leave. In a level 3, all areas within 5 miles of the coast, wateryways, and bays should leave.

[GeneratorPower]

I have found one thing particularly frustrating, and that is the media's portrayal of Tropical Storms vs. Hurricanes vs. Tropical Depressions. They often use the terms almost interchangeably. It seems scientifically more descriptive to use these categories, but the changeover from one to the other seems needlessly painful to me. For example, the difference between a 70mph TS and a 75mph hurricane is minimal. But to the public they are different enough to warrant vastly different action plans. I am in favor of highly descriptive terms and detailed categories for the scientific community, such as T-numbers. But for the public, I would prefer a simple term for TD's, TS's, and Hurricanes. Maybe we could say "Cyclone" for all three. Start naming them when they reach TS strength as we do now. Then give the public a non-linear scale with simple numbers, like decibels are used for sound. The damage difference between a 40mph TS and a 60mph TS is nowhere near as drastic as a 120mph Hurricane vs. a 140mph Hurricane. I say give 'em a 1-10 scale but put more divisions higher up and quietly take into account the size of the storm, the pressure, the forward speed's effect on max observed winds, etc. The public needs simplicity. Unfortunately they also need a dose of common sense.

[Javlin]

I agree MGC after Katrina much much more emphasis on the size in relation to surge aspect.I think that e lot of us here along the coast now have learned that lesson this year.But what about the other pieces of coastline that have not really sensed it yet.

[HurricaneBill]

I remember reading a chart of the SS Scale.

This was the descriptions of damage:

Category 1: Minimal

Category 2: Moderate

Category 3: Extensive

Category 4: Extreme

Category 5: Catastrophic

I think a big problem is the first two.

There's the perception that Category 1 and Category 2 hurricanes are no big deal because they are not major hurricanes. Yet, those are the winds most places will receive!

I remember when Isabel and Frances both weakened down to Category 2, there were some people who immediately said "Isabel's gonna be a dud" and "Looks like Frances is gonna be a flop."

In New England, a Category 1 or Category 2 can be destructive.
Look at Gloria (Yes, Gloria DID cause damage) and Bob!

I think the media needs to stop treating Category 1 and Category 2 storms as "wimpy".

[Ixolib]

Place much greater emphasis on the surge potential, and de=emphasize the wind potential. In other words, a storm of the same size, pressure, and winds approaching Miami will have a landfall much different than the exact same storm approaching the central Gulf Coast - but ONLY because of the surge. So, a storm might become a CAT 3 for Miami, but it would be a CAT 5 for the northern central gulf coast.

IMO, surge potential should become the new method of projecting, forecasting, and warning on landfalling hurricanes.

[Derek Ortt]

agreed Bil about the 1's and 2's needing far more respect

maybe the damage should read

1: Moderate
2: Extensive
3: Severe
4: Catastrophic
5: Incomprehensible

[wxman57]

agreed Bil about the 1's and 2's needing far more respect

maybe the damage should read

1: Moderate
2: Extensive
3: Severe
4: Catastrophic
5: Incomprehensible

The problem is that it's not just the peak sustained wind that could be in one tiny area of a hurricane - it's the whole structure of the hurricane that determines its destructiveness. Calling a hurricane a "Cat 3" because the plane finally was able to find a small pocket of Cat 3 winds as it left maybe shouldnt' qualify a hurricane as a Cat 3. Perhaps we should use an averaged max wind for the classification? What are the winds in the other areas around the center/eye? That way, a hurricane with 100kt winds all around the eye would be rated higher than one with a single squall producing 100 kt winds.

[Matt-hurricanewatcher]

agreed Bil about the 1's and 2's needing far more respect

maybe the damage should read

1: Moderate
2: Extensive
3: Severe
4: Catastrophic
5: Incomprehensible

The problem is that it's not just the peak sustained wind that could be in one tiny area of a hurricane - it's the whole structure of the hurricane that determines its destructiveness. Calling a hurricane a "Cat 3" because the plane finally was able to find a small pocket of Cat 3 winds as it left maybe shouldnt' qualify a hurricane as a Cat 3. Perhaps we should use an averaged max wind for the classification? What are the winds in the other areas around the center/eye? That way, a hurricane with 100kt winds all around the eye would be rated higher than one with a single squall producing 100 kt winds.

If the max winds where noted also to keep the record. I think what we can call this is the overall max winds. In which is the larger area of Max winds as you say. But right next to it can be the max max winds. But we can rate the storm by the overall max wind.

I think you have a alright idea. Something like this 80 mph max winds over a small area. Maybe no more then 6 nmi wide. Lets say there is a area wraping around the eye area of 75 mph.

So like this

80 max/overall 75 cat1 hurricane

I would also say that storms that once where cat5s normally still have there surge days after. Ivan was a cat5 over the southern Gulf of Mexico. In which had a very high surge. Katrina was a cat5 just 8 hours before landfall. In she was large which means a high surge.

[Pearl River]

Prior to 1970, there was no SS scale. People were told what kind of damage to expect. Since it is so widely stated on this board that basically no hurricane can be higher than a cat 3 at landfall on the northern GOM coast, then do away with the scale. Structures are built to higher standards these days, so a scale that is over 30 years old is not very accurate.

[Derek Ortt]

I would disagree about the absolute category rating being based upon something other than the max winds as it states what the worst hit areas can receive. However, we maybe should have a second rating in which the mean wind for the eye wall is (or mean wind for areas within the RMW)

[x-y-no]

I'd like to see a scale of hurricane size, in addition to the ss scale.

1 = small; size of Andrew, Charley
2 = medium; size of __________ (what was a medium-sized hurricane?)
3 = large; size of Katrina, Floyd
4 = extra large; size of Gilbert

They tell us how far out the tropical storm and hurricane-force winds go, but it's very hard to visualize or compare the size with only that information.

That was my idea too, except in my mind we lwould use bra cup sizes. i.e. Andrew = Cat 5-A, Katrina = Cat 3-D

[EDR1222]

The SS scale is good in that it gives the general public at least SOME idea of the potential threat. However, it fails miserably in completely defining the threat. The main failure is the SS scale ranks hurricanes according to one value alone - peak 1-minute winds. And then it assumes that all hurricanes are alike. Well, I can tell you, that all hurricanes are not alike, structurally.

Take a look at two "identical" storms (according to the SS scale). Both Dennis & Ivan struck the Gulf coast in about the same spot as 105 kt / 120 mph hurricanes. However, Ivan was 3 times the size of Dennis at landfall. As such, Ivan produced much more damage.

Don't assume that a hurricane's max wind field extends completely around the center. In many cases, peak winds may be found only in a tiny part of perimiter of the center. You can have a Category 3 hurricane with 100kt winds over 100 square miles, and you can have the "same" Category 3 hurricane with 100kt winds covering over 5000 square miles. Believe, me, the size of the wind fields and the extent of the higher wind speeds is a major factor in the potential destructive force (wind and storm surge).

Katrina was a Cat 3 hurricane at landfall, but hurricane force and greater winds extended much, much farther out than with a typical hurricane. Those high winds built up tremendous waves and an enormous storm surge. It's not the tiny areas of peak winds that build large waves and high surges, it's the expanse of lesser winds fields - something which the SS scale ignores.

These are some great points in my opinion. Some of these larger storms that the U.S. has experienced over the past couple years have been very costly. Frances is a good example as well.While only a cat 2 at FL landfall, it was a slow moving storm with a fairly large windfield and the damage was extensive through much of Florida.

[HurricaneBill]

That was my idea too, except in my mind we lwould use bra cup sizes. i.e. Andrew = Cat 5-A, Katrina = Cat 3-D

Wait a minute! Andrew wore a bra?!

[Scorpion]

Also, hurricanes differ in size. One hurricane will be fast moving, with a tiny area of Cat 3 winds. Another will be slow, huge, and have an enormous area of Cat 2 winds. I believe the Cat 2 winds over a period of time would cause more damage than brief Cat 3 winds. Also, the gust ratio over land is different. So if say a 100 mph sustained wind caused 140 mph gusts, I believe that would cause more in the line of Cat 3 damage than Cat 2. A 120 mph sustained wind might cause 160 mph gusts, which would cause more like Cat 4 damage. In conclusion I believe there are many discrepencies, but theres not really anything we can do about it. Revising the scale would probably get people confused. But I think that the size and storm surge should be more emphasized to the public than just the peak wind which only very few people will recieve.

[Derek Ortt]

Andrew was a LOT larger than Charley

How about this scale... keep the initial SS scale, but assign a letter afterwards based upon the following criterion

A: Hurricane force winds extend less than 25NM from center
B: 50NM
C: 75NM
D: 100NM
E: >100NM

Camielle would have been a 5-C at peak (likely a 4 or 3-C at landfall)
Katrina was a 3-D (5-D at peak)
Andrew was a 5-B
Charley and Iris a 4-A
Ivan a 3-B at landfall (hurricane winds did NOT extend more than 50NM from the center at landfall)
Rita a 3-C (I believe hurricane winds extended 60NM, but will wait for the final surface obs)
Wilma a 3 or 4-D (dont think they extended beyond 100NM) at Florida, a 5-A at peak, a 4-C at Yucatan
Frances a 2-C
Jeanne a 3-C
Isabel a 2-D