Time to scale back the scale

[BeauDodson]

Glad to see I am not alone in my thoughts concerning the scale

http://digitalmeteorologist.wordpress.com/2012/08/29/time-to-scale-back-the-scale/

At one of his last official functions as director of the National Hurricane Center, Bill Read spoke to the North Carolina Hurricane Workshop at East Carolina University. He told a room of more than 100 meteorologists, emergency managers, researchers, and other officials that there’s “no such thing as ‘justa’ category 1 storm.” Just ask anyone in the path of Irene, to take just the most recent example.

Yet, the fact that a storm is “‘justa’ category 1″ continues to be a reason for people not to evacuate, to under-prepare, and generally to ignore the risks that even ‘justa’ tropical storm would bring, much less a stronger system.

Then-Director Read even suggested the categories we apply to storms of this ilk may be doing us more harm than good.

[gymengineer]

What if further research went into refining an IKE-type scale that could be operationally reported by the NHC side-by-side with SS category? Would that help?

[am19psu]

The author of the article (@nsj), Brian McNoldy (@bmcnoldy), Bryan Wood (@bryanwx) and myself (@AmWx_Adam) spent some time talking about this today on twitter. I don't know how to post a twitter conversation, but I was arguing the same thing as gymengineer - using IKE as a separate scale to alert the public on the severity of surge.

[PSUBlizzicane2007]

Having separate wind/surge scales... possibly a separate scale for inland flooding... is certainly important. I know a lot of research has been ongoing since Katrina on methods to make surge better accounted for in categorisation of storms. I would have hoped we would have a better scale now put into practice, but I think we may only be a handful of years away from it actually occurring.

[icebreaker5221]

Although it doesn't address dangers from tornadoes or inland flooding, something like the Hurricane Severity Index (HSI) would more appropriately address the risk:

http://felix.impactweather.com/hsi/hsi.pdf

[phil882]

The author of the article (@nsj), Brian McNoldy (@bmcnoldy), Bryan Wood (@bryanwx) and myself (@AmWx_Adam) spent some time talking about this today on twitter. I don't know how to post a twitter conversation, but I was arguing the same thing as gymengineer - using IKE as a separate scale to alert the public on the severity of surge.

I think this is a good idea... and while we are at it, why not revise ACE as well so that its dependent on storm radius. I can asure you that a small TC like Hurricane Iris (2001) does not have the same energy content as a large TC of the same intensity (Igor for example). If ACE is dependent on how long a storm have persisted for, it should also be dependent on how large their wind radius becomes.

[turtlehurricane]

Didn't the NHC already try and fail to improve the scale? All they did was remove pressure requirements lol...

[gymengineer]

Or what about separating out each aspect fully into some sort of integrated scale? So, a hurricane might be rated: 1/3/3 (1 for winds, 3 for storm surge, 3 for inland flooding potential). There are hurricanes that would be a 1/1/1 on that type scale, and therefore, it wouldn't make sense to evacuate the same number of people for a 1/1/1 type-storm than a storm like Isaac. Inland flooding would be the most imprecise, but storm surge forecasting has been really solid lately.

Edited to add: What I'm thinking of is a system like TS Hannah- almost a hurricane. I totally get what folks are saying that people need to take all storms seriously, etc. But if Hannah had just strengthened a tad more, it would have made landfall as a Cat 1 hurricane and still "only" have done pretty minimal damage. Having some sort of scaled value to give to the public would help them distinguish better between a Hannah-type-landfall and an Isaac-type-landfall.

[hm8]

Having separate wind/surge scales... possibly a separate scale for inland flooding... is certainly important. I know a lot of research has been ongoing since Katrina on methods to make surge better accounted for in categorisation of storms. I would have hoped we would have a better scale now put into practice, but I think we may only be a handful of years away from it actually occurring.

Or what about separating out each aspect fully into some sort of integrated scale? So, a hurricane might be rated: 1/3/3 (1 for winds, 3 for storm surge, 3 for inland flooding potential). There are hurricanes that would be a 1/1/1 on that type scale, and therefore, it wouldn't make sense to evacuate the same number of people for a 1/1/1 type-storm than a storm like Isaac. Inland flooding would be the most imprecise, but storm surge forecasting has been really solid lately.

I agree that basing a cyclone's rating solely off of wind speed can be misleading as to the amount of damage it may cause. However, I feel like having separate scales for wind, surge, flooding, etc. would over-complicate the matter. Having a storm rated in multiple ways with different severity levels in each scale could make it confusing to the average person as to what precautions they should take to stay safe. Remember that a good amount of people don't know the difference between a severe wx watch and warning, so that's why scale as simple as the Saffir-Sampson is appealing.

[NJDEVIL]

The prospect of judgement based on maximum sustained winds is a flaw in my opinion. As an example, the public hears maximum sustained winds of 80MPH and does not realize that gusts of over 100 MPH are not out of the question. We're also estimating the maximum winds in most cases, so accuracy is moderate at best.

We don't need to totally abandone the current scale, for one, systems that are no threat to land do not need any excessive lable or warning. Most effects of a tropical cyclone can be warned with our current watch system, such as flood watches and tornado watches, but we don't currently have a system in place for storm surge.

Perhaps a seperate storm surge warning (low/moderate/high/excessive) system can be implimented.

[PSUBlizzicane2007]

I agree that basing a cyclone's rating solely off of wind speed can be misleading as to the amount of damage it may cause. However, I feel like having separate scales for wind, surge, flooding, etc. would over-complicate the matter. Having a storm rated in multiple ways with different severity levels in each scale could make it confusing to the average person as to what precautions they should take to stay safe. Remember that a good amount of people don't know the difference between a severe wx watch and warning, so that's why scale as simple as the Saffir-Sampson is appealing.

I disagree. If it is pounded into the public's head, they will understand.. and the vast majority of the public in danger from surge and wind understand the difference. It's just now we have a sole wind speed number which is actually what confuses things when it comes to storm surge.

If everywhere, in all bulletins and media, it is said over and over again "this is a wind category 1 and a surge category 3"... people will understand. It's not that difficult.

[PSUBlizzicane2007]

Or what about separating out each aspect fully into some sort of integrated scale? So, a hurricane might be rated: 1/3/3 (1 for winds, 3 for storm surge, 3 for inland flooding potential). There are hurricanes that would be a 1/1/1 on that type scale, and therefore, it wouldn't make sense to evacuate the same number of people for a 1/1/1 type-storm than a storm like Isaac. Inland flooding would be the most imprecise, but storm surge forecasting has been really solid lately.

Edited to add: What I'm thinking of is a system like TS Hannah- almost a hurricane. I totally get what folks are saying that people need to take all storms seriously, etc. But if Hannah had just strengthened a tad more, it would have made landfall as a Cat 1 hurricane and still "only" have done pretty minimal damage. Having some sort of scaled value to give to the public would help them distinguish better between a Hannah-type-landfall and an Isaac-type-landfall.

Inland flooding would be best rated on a 3-tier system of High/Medium/Low threats. There really isn't a reason to have a 1-5 category system like with wind and surge.

[gymengineer]

Inland flooding would be best rated on a 3-tier system of High/Medium/Low threats. There really isn't a reason to have a 1-5 category system like with wind and surge.

I agree.

[isohume]

The general public often has issues understanding the difference btw a watch and a warning. How would a multi-layered or no-scale hurricane warning system help by saying some parts of the storm may not be too bad, yet other parts could be bad?

In general...folks rely on their past personal experience as to how they will react to a similar situation. With more inherent confusion and more room for a certain layer or description to be "wrong" in their area...there would probably be less folks seeking appropriate shelter under such a system.

[HKY_WX]

If the scale is for met' purposes it's fine. But if it's intended to save lives, it needs to be revamped, or perhaps have a scale for met's and a scale for the public. When the public sees "category 1", they think no big deal. As we can see now, that's totally inaccurate.

[turtlehurricane]

If the scale is for met' purposes it's fine. But if it's intended to save lives, it needs to be revamped, or perhaps have a scale for met's and a scale for the public. When the public sees "category 1", they think no big deal. As we can see now, that's totally inaccurate.

We need scales for surge, wind, and rain. Isaac had category 1 winds, category 2-3 surge, and category 4-5 rainfall.

[CT Rain]

We need scales for surge, wind, and rain. Isaac had category 1 winds, category 2-3 surge, and category 4-5 rainfall.

I'm not sure I agree. I think all this may do is confuse the public even more.

Take for instance someone who lives on a river and lives through a "rain-5" hurricane. The bulk of the rain, however, fell 300 miles west of where that person lives. The next time there's a "rain-5" storm moving at them they may say "no need to worry about rising waters... the last storm was sort of blah here."

Same thing with surge. When we assign a category to a storm that is hundreds and hundreds of miles wide people immediately think their town will get that "scale" impact. Someone in central LA is going to have a dramatically different experience than Plaquemines Parish than downtown NOLA than coastal Alabama.

TBH I think a tiered multi-aspect scale may do more harm than good.

At the end of the day it's effective messaging by emergency management and the media that will get the appropriate word out.

[phlwx]

I'm not sure I agree. I think all this may do is confuse the public even more.

Take for instance someone who lives on a river and lives through a "rain-5" hurricane. The bulk of the rain, however, fell 300 miles west of where that person lives. The next time there's a "rain-5" storm moving at them they may say "no need to worry about rising waters... the last storm was sort of blah here."

Same thing with surge. When we assign a category to a storm that is hundreds and hundreds of miles wide people immediately think their town will get that "scale" impact. Someone in central LA is going to have a dramatically different experience than Plaquemines Parish than downtown NOLA than coastal Alabama.

TBH I think a tiered multi-aspect scale may do more harm than good.

At the end of the day it's effective messaging by emergency management and the media that will get the appropriate word out.

I think the hangup on tropical storm/hurricane is a huge barrier. Media needs to do a better job of communicating that a large 70 mph tropical storm that eventually will nudge to a 80 mph hurricane isn't a mere "Don" or run of the mill tropical system that just rains and farts some gusty breezes out. You don't have to hype it to the next Katrina (hi JB) but setting clear, realistic expectations of what the storm will do is sufficient.

Worrying about the hangup on TS/Cane is a bit silly...5 mph isn't a substantial barrier except for the human psyche and some tropical weenies.

[CT Rain]

I think the hangup on tropical storm/hurricane is a huge barrier. Media needs to do a better job of communicating that a large 70 mph tropical storm that eventually will nudge to a 80 mph hurricane isn't a mere "Don" or run of the mill tropical system that just rains and farts some gusty breezes out. You don't have to hype it to the next Katrina (hi JB) but setting clear, realistic expectations of what the storm will do is sufficient.

Worrying about the hangup on TS/Cane is a bit silly...5 mph isn't a substantial barrier except for the human psyche and some tropical weenies.

Did that happen? I didn't hear that anywhere.

For example in Irene (a TS) last year... given the arrival time and already high tide we were hammering home the idea that the storm would have the most serious surge in some parts of the state in decades... worse than many hurricanes!

[gymengineer]

I think the hangup on tropical storm/hurricane is a huge barrier. Media needs to do a better job of communicating that a large 70 mph tropical storm that eventually will nudge to a 80 mph hurricane isn't a mere "Don" or run of the mill tropical system that just rains and farts some gusty breezes out. You don't have to hype it to the next Katrina (hi JB) but setting clear, realistic expectations of what the storm will do is sufficient.

Worrying about the hangup on TS/Cane is a bit silly...5 mph isn't a substantial barrier except for the human psyche and some tropical weenies.

Taking that discussion out of the way and just comparing hurricanes to hurricanes, you still have the issue of the discussion in this thread: How useful really is the SS scale? It's by far the most widely used metric for the general public of how "bad" a hurricane is going to be. So since a hurricane can be much, much worse than what just reading the SS damage description (based only on wind damage) would indicate because of storm surge and flooding, the question is should there be a different metric used in public releases?

Or, if people believe that the public will ignore warnings no matter what and get confused by more criteria, then why not just de-emphasize the SS scale from public releases altogether and save the scale mainly for historic study, as suggested in this thread?

[Clinch Leatherwood]

I'm not sure I agree. I think all this may do is confuse the public even more.

Take for instance someone who lives on a river and lives through a "rain-5" hurricane. The bulk of the rain, however, fell 300 miles west of where that person lives. The next time there's a "rain-5" storm moving at them they may say "no need to worry about rising waters... the last storm was sort of blah here."

Same thing with surge. When we assign a category to a storm that is hundreds and hundreds of miles wide people immediately think their town will get that "scale" impact. Someone in central LA is going to have a dramatically different experience than Plaquemines Parish than downtown NOLA than coastal Alabama.

TBH I think a tiered multi-aspect scale may do more harm than good.

At the end of the day it's effective messaging by emergency management and the media that will get the appropriate word out.

100% agree. People will either pay attention or they won't. We put warnings on cigarettes telling people they will die if they smoke them, they still smoke. We tell people being fat will kill you and yet we're heavier than ever. You cannot legislate or mandate out the stupidity in society. I think NOAA should do a better job of getting the message out to people like you that are front and center in the media so that the message is clear. We had comparisons to Katrina when in reality anyone with a brain that looked at this saw it as a weak TS and said "nothing to worry about" because the headline should have been "strong winds but biggest threat is severe flooding like Katrina" If we go to all these different systems it's going to get ridiculous. NOAA should work on better communication with the public media and leave the wind system alone.

[gymengineer]

Another way to look at this: In recorded American history, the most deadly phenomena in a hurricane has alternated between storm surge flooding and fresh water flooding. How did a wind scale become the most widely accepted and released to the public measure of potential impact from a hurricane?

[Quixotic1]

We need scales for surge, wind, and rain. Isaac had category 1 winds, category 2-3 surge, and category 4-5 rainfall.

This. A good idea, however since the public gets confused about these things, maybe use them in a formula to determine a single category? Something like:

wind x pricipitation rate x 1/(storm directional speed) = category.

Its simplistic but you get the idea. Wind is not enough. Charley was a deadly storm and it was only a depression when it did its damage.

[turtlehurricane]

This. A good idea, however since the public gets confused about these things, maybe use them in a formula to determine a single category? Something like:

wind x pricipitation rate x 1/(storm directional speed) = category.

Its simplistic but you get the idea. Wind is not enough. Charley was a deadly storm and it was only a depression when it did its damage.

That is a better idea, multiple scales would probably get out of control.

C = ((W/Wavg1) + (R/Ravg1) + (S/Savg1))/3

C is the category, W is the wind speed, R is the rainfall rate, and S is the surge. The subscript avg1 is the average conditions in a category 1 hurricane... so everything is normalized. Obviously this equation would need to honed in with lots of data to work, but the point is a category 3 is 3X stronger than a category 1 and so forth. Seems logical enough.

So for Isaac, we'll say 85 mph winds, 18" of rain somewhere, and 12' of surge. We'll say cat 1 averages are 75 mph, 6 inches, and 7 ft. That's a category 2.26. Definitely need a better equation though for this to be useful, gotta find the mathematical relationships between wind and damage, rain and damage, etc. They're not linear.

[Smitty97]

Perhaps using a decimal like earthquakes would help people understand. I would guess that most people know a 4.9 earthquake is nearly 10 times as powerful as a 4.0.

Develop some equation based on wind, surge, rain, possibly energy, and reduce it to some x.y number on a log scale.

[NECT]

I'm not sure what the right way to go is, but, in the end, if there's a hurricane coming, it's going to be bad for someone. IMHO, a big part of the problem is that it's still difficult to pinpoint the exact track, where landfall and the highest winds will be will be, where the worst of the surge will be, and where the heaviest rains will be. People on the coast will be vulnerable, but we still can't predict exactly where far enough ahead of time to guarantee that evacuations will be necessary in specific areas, but we know it's likely that someone should be getting the hell out of the way. So someone who chooses not to evacuate for one hurricane, rides it out, and is spared the worst. Next time the ride it out, they get slammed and wish they had got the hell out.

The message people need to get is that by the time we really know who should have left, it's too late.

[WidreMann]

Perhaps using a decimal like earthquakes would help people understand. I would guess that most people know a 4.9 earthquake is nearly 10 times as powerful as a 4.0.

I don't think people actually know that the Richter scale works like that. I think they think that a 5 is "one more" than a 4. So let's stay away from logarithmic scales.

[Dunkman]

I think coming up with some complicated equation is a terrible idea. What's worse than people going through several category 1 hurricanes and thinking they aren't bad only to have one that is? People going through that same process with storms called category 3. Storm surge is such a localized thing that it is very difficult to come up with a universal system to quantify it. You could say the same with flash flooding although to a lesser extent. Some of the worst storm surge flooding I ever experienced on the NC coast was because a storm stalled in such a place with the winds in just the perfect direction to cause a massive rise down a small river that just happened to be heavily populated.

I don't disagree with getting rid of the scale. I just don't think you should replace it with another scale that is more complicated but doesn't really solve any problems. What about a small, fast moving storm where the east quadrant will land in an area that isn't susceptible to storm surge and won't drop more than a few inches of rain? So yeah, it has 130mph winds but it will have a cat 1. surge and a TD flash flood potential so lets call it a category one. How is that any better? What I would support is just removing the category and perhaps keeping the major hurricane distinction. Instead, put much more focus on localized forecasts (and getting that information to the public...seriously what % of the public reads a storm surge map...) and maybe even a separate warning system for storm surge and leave the hurricane warnings for wind only.

[NECT]

I think coming up with some complicated equation is a terrible idea. What's worse than people going through several category 1 hurricanes and thinking they aren't bad only to have one that is? People going through that same process with storms called category 3. Storm surge is such a localized thing that it is very difficult to come up with a universal system to quantify it. You could say the same with flash flooding although to a lesser extent. Some of the worst storm surge flooding I ever experienced on the NC coast was because a storm stalled in such a place with the winds in just the perfect direction to cause a massive rise down a small river that just happened to be heavily populated.

I don't disagree with getting rid of the scale. I just don't think you should replace it with another scale that is more complicated but doesn't really solve any problems. What about a small, fast moving storm where the east quadrant will land in an area that isn't susceptible to storm surge and won't drop more than a few inches of rain? So yeah, it has 130mph winds but it will have a cat 1. surge and a TD flash flood potential so lets call it a category one. How is that any better? What I would support is just removing the category and perhaps keeping the major hurricane distinction. Instead, put much more focus on localized forecasts (and getting that information to the public...seriously what % of the public reads a storm surge map...) and maybe even a separate warning system for storm surge and leave the hurricane warnings for wind only.

Exactly.

Meteorologists have a deep understanding of what's going on, what makes for a dangerous storm, which models are reliable for what aspects, but predicting exactly where the worst conditions will be is still difficult. So many mets work for media outlets, and there's a lot of pressure to make forecasts.

How about, there's a hurricane coming, and it's going to be close to you. If you're in it's path, you're probably going to wish you had gone somewhere else.

[Windspeed]

I believe surge and flood forecasting with tropical cyclones is even more difficult than pressure and wind intensity forecasting. Granted, we have modeling to help; however, let's be very clear, even with respect to Isaac, the storm could have been an entirely different animal had it slowed to a crawl well inland versus right on the coastline. Isaac's eyewall spent nearly 18 hours over or adjacent to the coastline while still in a state of intensification. Additionally, it has been abnormally slow to weaken based on its proximity to the coastline combined with landform it is traversing. How often does this scenario occur? Isaac is a rare hurricane and even harder to predict days in advance. I simply don't believe anyone could have predicted this scenario with confidence in it verifying without just being lucky. Yes, some will say a few of the models showed a stall at the coastline, but not on every run. Heading into the last few days, the biggest worry to me as far as surge potential was the fact the storm did have a large circulation versus an average tropical surface low. But even a large circulation does not respond with the type of surge and flooding we have seen with Isaac as compared to the norm. Forward motion and steering currents have been as much a factor. But this combination of forward motion and organization is an afterthought compared to the following sad realization: Though meteorology has advanced light years thanks to computer modeling and reconnaissance, it cannot supplant the complacency that exists in our society. Complicating or reorganizing the scale that has been in place for decades is not a guarantee of change within public perception. Not the same public that spends eight-to-twelve hours a day glued to social media, reality TV and network news commentators. Most of the people that frequent these weather forums, or any earth science related forum, or that are just generally interested in the natural world, tend to pay attention to the potential of every single tropical cyclone or natural hazard event. You, the person posting here, takes every event seriously because most of you have grown to expect there is always a possibility of a worse scenario unfolding than the expected. Most of you spend more time learning about your surroundings. The point I am trying to make here is that radical changes to the scale that is in place, based on an abnormal event (Isaac) as compared to "the norm" and what we generally may think in retrospect to this event, might just make things far more difficult for forecasting and exponentially increase error in verification. And this, in turn, could just make it more confusing for the crazed media and general public when those errors are revealed. Example: This hurricane was forecasted to be a greater surge threat as a category one than the normal category one and it did not pan out. Understand, I am not saying we can't just get rid of the scale altogether. I just think that every hurricane is different and expectations based on scale alone is flawed because intensity forecasting is still so difficult. At one point, Isaac was forecasted to reach major hurricane status in the GOM. That it did not may be the biggest reason people did not evacuate low-lying or areas below sea level. "This isn't Katrina" ... "This isn't Camille" ... "This isn't Andrew" ... the problem with this flawed idiology is that neither of those hurricanes are alike either, and they were all category five hurricanes. And yet, here we are discussing the problems of having a scale in place.

The bottom line is regional and local authorities, the media, and better yet, the public themselves, have got to take every hurricane seriously. No, not every hurricane is the same. And this goes to the point. We are not yet capable of telling the public with a high percentage of accuracy what will unfold with one tropical storm or hurricane event in the same category in scale versus another tropical storm or hurricane in the same category because there is still too much unpredictability and error. This just leads to a higher degree of missed forecasts and a greater degree of public missunderstanding and even misstrust. I believe the changes that have been made with respect to scale and the "Ike" factor by the NHC have been sufficient. But in retrospect, the abnormal occurrance of hurricane like Isaac is going to happen, even if rare. The solution to overcoming situations that ocurred this week with Issac is quite straight-forward. If you (the general public) live on the coastline and you have a tropical storm or hurricane forecasted in your general direction, you always prepare for the worst case scenario, whether you choose to evacuate or you stay in your home. Often as not, the inaccuracies of intensity forecasting make focusing on categories unwise. If you live in a low-lying area or below sea-level, you are going to always be unwise NOT to evacuate. If you live in a mobile home, you are going to always be unwise to NOT evacuate. Sometimes weather forecasters get it wrong. Sometimes the unpredictable nature of weather phenomenon make it so your expectations do not pan out. If you evacuate and your location receives minimal impact or the hurricane is weaker than expected, never base your next decision on the previous event. Know the next storm might kill you. And if you choose not to evactuate and the storm is not nearly as bad as expected, then count yourself lucky and remember that basing your decision on luck will inevidably put you and your family in a life-threatening situation. If the inconvenience of dealing with mother nature on a coastline is an acceptable part of your lifestyle, then do yourself a favor and always expect the worst. And yet, I am probably wasting thought on this myself. Inevidably, some people (or now seemingly most) have to learn the hard way....

In finishing, I will say that I don't believe making changes to the scale or creating new ones will fix the problem we experienced this week. It may be that removing the focus on scale in advisories is worthwhile or that re-educating the media from focusing on scale is worth consideration. But I am not so optimistic that even these changes will motivate people to evacuate when they otherwise choose not to based on intensity forecasts. It may be that this hurricane is a real lesson that all tropical cyclones should be taken seriously because all have the "unpredictable" potential to put you in a life-threatening situation. But in the end, that is going to be up to the individual and their personal responsibility.