Storm Rating Scales: Overrated!

It seems some winter weather experts and aficionados couldn’t resist the temptation to leap onto the destructive-scale competition bandwagon. I’ve seen this coming but haven’t felt that it was worth my time to utter personal comments until now:

Northeastern Snowfall Impact Scale (NESIS), and a FOX News story about its debut.

At least this scale’s documentation makes it clear from the start — it’s largely not about meteorological comparison, but about societal impact and population size, its strong secular influences. I respect that element of honesty in the documentation of its deepest flaw (secularity). It is not a scientific measure but instead a grab bag of weather and non-weather elements assembled for some form of “impact assessment.” Fine. As long as that caveat always accompanies usage of the scale with a big fat asterisk, great. In the media world of ten second attention spans, though, I bet it won’t.

It is what it is, nothing more, nothing less. Just don’t make it out to be more!

Well-conceived ratings scales *are* as useful way to relate actual or potential danger to media and public in a readily comprehensible (albeit grossly oversimplified) way, and have shown some merit. I can accept them, even use them as intended, though not without considerable reservation. It’s like being tolerant of that good friend who forgot to use his armpit deodorant for three days straight — likeable but smelly; hold your nose and carry on with the conversation. 🙂

The Enhanced Fujita Scale is an example, imperfect but a distinct improvement upon its predecessor in that many more modes of damage can be used to rate an event. Still, its primary, systematic flaw is in its inability to account for tornado strength where there are a lack of sufficiently strong structures to sample the worst of the winds. The scale is not too simple anymore, but still depends much too much on judgment calls and whether anyone’s building or utility tower happened to stand in the way.

The Saffir-Simpson Scale for hurricanes has its problems too — namely an inability to account for storm size or some assessment of total energy release which would more robustly assess the storm’s total fury. At least this scale has, as its fundamental basis, a distinct, meteorologically measurable quantity without secular population biases involved. This scale depends far less on judgment calls than the EF Scale, but is way too singular. Hurricanes are far, far more than one wind speed maximum located somewhere in the inner core! Yet, by employing a painfully oversimplified scale, that’s precisely the notion we fallaciously convey: the storm is a point phenomenon and not a force over an area.

I can deal with some form of rating scale as long as it is more independent of secular factors. If a rating system for blizzards is developed for more general and meteorologically meaningful use than NESIS, it had better not account for something as totally capricious and nonmeteorological as number of people underneath.

Simply put, the atmosphere doesn’t give a damn how many people are under the snow band!

And who is so arrogant as to say that the fifty ranchers and 5,000 small-town residents affected by a ND event are less important than the three million suits and ties in DC anyway? Consider the Schoolhouse Blizzard of 1888 in the northern Great Plains. Just try to tell any of those affected, if you could go back in time, that their storm wasn’t worthy of all time rank because it didn’t happen to take a great big dump all over a comparatively tiny strip of land between Alexandria VA and Portsmouth NH that was and is grotesquely overpopulated.

The whole thing seems to pander to a pop-weather fad culture propagated by the tabloid “shockumentary” ethos and epitomized by the likes of Storm Stories and “extreme storm chasing.”

It also looks to be a rather unnecessary exercise in oversimplification and competitive drag racing of what truly are complex and often incomparable phenomena.

The solution, as often, is simple: Assess and analyze storms on their own merit, by nature of their own unique characteristics and effects. And if they must be ranked, use the most strictly meteorological, scientifically robust, statistically derived, measurable and repeatable variables available at the time.

Those are my initial impressions.

And it once again beckons a more fundamental question: Why our obsession with competition and rank of storms, and to that end, oversimplifying storms’ characteristics for the sake of what basically are no more than bragging rights?

By the way, my storm’s bigger than your storm and I’ve got the scale that says so. NYAAAAH!

[Thanks, MAD4caster, for reminding me of this after a long period of forgetfulness, and for letting me know of the news link. ]


6 Responses to “Storm Rating Scales: Overrated!”

  1. bc on January 31st, 2006 11:12 pm

    Next thing you’ll know they’ll have drought and flood scales. I can envision a scale going from “toad strangler” to “Genesis”. I guess it doesn’t matter if you froze to death in a NESIS 1 or a NESIS 2 or got mangled in a F3 or a F4…dead is dead. That’s the only scale we need to be worried about.

  2. TL on February 21st, 2006 12:41 pm

    Uh, they already have a drought rating scale. It’s called the Palmer Drought Index.

  3. tornado on February 27th, 2006 9:59 pm

    I know. What’s your point?

  4. SK on March 2nd, 2006 6:07 pm

    A Relative Severity Index for Tornado Events (RSITE): An Index to Describe the Effects of a Tornado on Individual Communities
    The Fujita Scale was intended to rate the power associated with a tornado, but not the actual effects it had on the community it affected. Currently, there is no classification system for tornado events that measures, classifies, and rates actual losses in terms of the effects on people and the economic losses to their communities. While the Fujita Scale is universally accepted as the method by which tornadoes are classified, I believe a niche exists to create a classification system that measures the effects on people and their communities. This is what I aim to do. In addition to categorizing tornado events as F0 to F5 based on subjective post-event observations, why not use information about the effects on people and the community to build a composite index which describes the damage done to a specific community?

    The Relative Severity Index for Tornado Events (RSITE) will utilize variables such as injury and/or death of people, loss of structures, and other economic factors to describe how a specific tornado has affected their community. A scale that assigns a relative rating to the damage incurred will allow the severity of the storm to be understood in terms of its effect on a specific community, rather than an absolute rating that gives only a broad, general indication of its effects.

  5. tornado on March 3rd, 2006 11:09 pm

    This is a joke, right? The last thing we need is more storm ratings that are even more heavily based on pure human artifice (where people are) than on the *meteorology* of the event. Once again: The physics of the atmosphere are independent of sociogeography. Put another way, the atmosphere does not care about political boundaries!

  6. Scott on March 27th, 2006 7:12 pm

    “By the way, my storm’s bigger than your storm and I’ve got the scale that says so. NYAAAAH!”

    Love it…

    For a while after the April 10, 1979 F4 tornado in Wichita Falls, TX, I saw storm-battered cars driving around with bumper stickers reading “Our Tornado Is Bigger Than Your Tornado! Wichita Falls, TX”. I spotted some of these as far away as Dallas, where I was living then (I’m a WF native, for what it’s worth).

    Judging by a statement I read on the NWSFO Norman Web site about that event, there are still some people who are annoyed that the storm wasn’t rated F5. Who knows, maybe with the new EF scale, somebody will go back and look at the damage photos and retroactively change it. hehe

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