Hurricane Rating System

[WXTransplant]

I vaguely remember this being discussed during Ike but wasn't there some discussion about possibly altering the hurricane rating system to include more than wind? I believe with Ike surge potential was mentioned, and I wonder what people think about flood potential? Irene was only a Cat 1, but the flooding did some serious damage. To people who don't really follow the weather but hear "minimal hurricane" or "it's now only a tropical storm" in passing are the ones that need to rescued later on when the they're trapped upstairs due to raging flood water from what sounded like was not going to be a big deal. I was just wondering if anything is being done to change the system, or if people even felt it needed to be changed?

[dan88]

While there are scales that include more than just maximum sustain winds, most noticeably the Integrated Kinetic Energy scale, it would be very hard to include fresh water flood potential into any scale. The main reason for this are that it would be far more subjective than any objective scale. For example, a scale including fresh water flood potential would have different ratings based upon speed, forecast track, geography upon where it is suppose to track, recent weather along the track (much of Irene's flood potential came from the fact that there has been exceptionally heavy rains over parts of the North East before Irene), and so on. It would be nearly impossible to give a meaningful rating to such a system, and the rating would need to be changed greatly with each small shift over the forecast track, or each small change in forward speed.

[am19psu]

While there are scales that include more than just maximum sustain winds, most noticeably the Integrated Kinetic Energy scale, it would be very hard to include fresh water flood potential into any scale. The main reason for this are that it would be far more subjective than any objective scale. For example, a scale including fresh water flood potential would have different ratings based upon speed, forecast track, geography upon where it is suppose to track, recent weather along the track (much of Irene's flood potential came from the fact that there has been exceptionally heavy rains over parts of the North East before Irene), and so on. It would be nearly impossible to give a meaningful rating to such a system, and the rating would need to be changed greatly with each small shift over the forecast track, or each small change in forward speed.

Good answer. Here's more on IKE.

http://www.aoml.noaa.gov/hrd/ike/

[donsutherland1]

While there are scales that include more than just maximum sustain winds, most noticeably the Integrated Kinetic Energy scale, it would be very hard to include fresh water flood potential into any scale.

I believe post-event, a more comprehensive rating that includes precipitation (perhaps modeled after the NESIS scale for the precipitation component) would enhance an evaluation of the Hurricane's impact.

[Juliancolton]

I think more efforts should be made to simply educate the public on the dynamics of a hurricane, rather than trying to develop an inevitably incomprehensive scale. My view is that so long as we categorize hurricanes, the general public will continue to make decisions and judgements based on the number the storm has been assigned. A Category 1 is nothing to worry about, simply because it's not a 4 or a 5; that's how it works in most homeowners' minds. Until more people understand, even to a minimal extent, how a hurricane works and how it does its damage, we'll continue to see poor pre-storm judgements and unfair post-storm quips.

Residents of NYC expected palm trees to fly by and a stadium effect eye in which to assess the skyscrapers that would surely be reduced to rubble by Hurricane Irene. They went to stores and bought milk, bread, and eggs by the cartfulls, because that's what they hear they need (either that, or there's a French toast competition somewhere). And when palm trees failed to become airborne and skyscrapers remained upright, they assumed the weather men deliberately lied to them, they've wasted all their time and money, and that every storm from here on out would without doubt be equally as disappointing. I really couldn't believe how many bloggers and reporters wrote entire pieces on how the storm was overhyped, and how it was little more than a typical nor'easter, when in reality it's proving to be one of the worst storms in United States history in many ways.

[donsutherland1]

I think more efforts should be made to simply educate the public on the dynamics of a hurricane, rather than trying to develop an inevitably incomprehensive scale. My view is that so long as we categorize hurricanes, the general public will continue to make decisions and judgements based on the number the storm has been assigned. A Category 1 is nothing to worry about, simply because it's not a 4 or a 5; that's how it works in most homeowners' minds. Until more people understand, even to a minimal extent, how a hurricane works and how it does its damage, we'll continue to see poor pre-storm judgements and unfair post-storm quips.

Residents of NYC expected palm trees to fly by and a stadium effect eye in which to assess the skyscrapers that would surely be reduced to rubble by Hurricane Irene. They went to stores and bought milk, bread, and eggs by the cartfulls, because that's what they hear they need (either that, or there's a French toast competition somewhere). And when palm trees failed to become airborne and skyscrapers remained upright, they assumed the weather men deliberately lied to them, they've wasted all their time and money, and that every storm from here on out would without doubt be equally as disappointing. I really couldn't believe how many bloggers and reporters wrote entire pieces on how the storm was overhyped, and how it was little more than a typical nor'easter, when in reality it's proving to be one of the worst storms in United States history in many ways.

IMO, the NHC and NWS do a fantastic job educating the public. Unfortunately, there are diminishing returns to the extent of that education. The reality is that human psychology plays an important role in shaping future behavior. When events prove less severe than expectations over a period of time, complacency sets in. Once complacency sets in, there are significant limits to what one can do to assure that the public responds appropriately. There will likely come a time when a Category 3 storm does make landfall in the Northeast and the risk is probably growing that the public, conditioned by events that failed to measure up to their expectations, will treat things too lightly. Such a problem is not limited to weather, only. One sees that same pattern across the board when it comes to responsiveness to risk. For example, complacency reigned during the run-up in housing prices into mid-2006. IMO, a dose of complacency reigned in New Orleans prior to Katrina's landfall even as the NWS posted apocalyptic warnings, as the city was largely spared the brunt of major hurricanes going back to 1947.

[eurojosh]

I agree that there might be a use for a more outcome-related/predictive system, rather than a wind-based one. Models for such systems do already exist in meteorology, for example in the Northeast Snowfall Impact Scale (NESIS) system, which grades the severity of winter storms based on a weighted combination of snowfall amount, area covered, and the number of people in the path of the storm. Applying a similar system to Hurricanes, where possible, does have the attraction of reducing 'hype' and allowing people to focus on the true major storms - so, for example, a CAT 3 grazing the OBX might have a lower rating than a TS hitting NYC and New England.

There are two obvious flaws to such a scheme. The first is the predictability factor - it is far easier to sit back in the wake of a weather event and assess the damage, than it is to preemptively categorize it. NWS issues Tornado Warnings, for example, but not Fujita Scale predictions; similarly, it issues Winter Storm Warnings, but not NESIS projections. Expanding the prediction issue to a local vs national profile, while a TS in NYC may rank greater in a NESIS-like scale than a CAT-3 near OBX, we wouldn't want to under-state the threat to those in, say, Cape Hatteras.

Perhaps the answer is to provide two numbers to each storm: its Saffir-Simpson scale as an indicator of strength and potential to do local damage, as well as a NESIS-like overall damage potential scale. So, for example, we might see things like:

Irene (at landfall): 1/3 (i.e. CAT 1, Threat 3)

Katrina (at landfall): 3/5

Applying such a system to a wider spectrum of meterological events would also, perhaps, allow for greater anticipation of consequences. For example, developing some sort of weighted system that could account for the potential destruction based on strength and population affected not only of hurricanes, but also of winter storms, tornado outbreaks, and other predictable phenomena (who knows, to include geophysical phenomena like earthquakes and volcanos one day if/when they become predictable) might be useful. But the underlying problem is with the potential for bust, and loss of faith in the system.

The Times of London once famously ran a competition for most boring headline. The winner was "Small Earthquake in Chile, Not Many Dead." It could equally have been 'Small Hurricane at 28N 44W, Not Many Boats Affected.' The same could not be said of the same storm several hundred miles further West. Addressing the perceptions paradox when it comes to human impact is a worthy point of discussion when it comes to bridging the gap between science and popular culture.

Just sayin'....

[WXTransplant]

Thanks for the great discussion, and some good points were raised. I think it might be something to think about for future storms if possible. I personally feel like something needs to be done the emphasize the water threat from these storms, not just the wind. Princeton, NJ had an EMT die attempting to search a submerged car during the storm. I think the people who say it's no big deal need to realize they might not be just putting their own lives in danger when it does become a big deal.

[dan11295]

I think by now the public has some more awareness that "larger hurricane=more surge". However trying to revise the rating system to account for this might result in more confusion than its worth. Especially since factors other than a storms size and strength can impact surge, including the angle of approach to the coast, the distance of the continental shelf off the coast, etc.

Warnings scales based on rainfall are also tricky. Ten inches of rain in Vermont is going to cause a lot more damage than in North Carolina due to topography and soils. Previous rainfall is another factors. Many storms hit hit without freshwater flooding being an important component. Then you have events like Allion, Floyd and Irene where flooding is a major cause of damage.

The point is every situation with every storm is unique. trying to account for too many variables is probably not advisable.

[SluggerWx]

If this was 'over-hyped' and Irene took 38 lives, how many lives would have been lost if people perceived it to be 'under-hyped?'

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