Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[CoreySamson]

So I mentioned this in the "Minor Things that Bother You" thread, and I thought it would be interesting enough to share. The current Saffir-Simpson Wind Scale, while very good at indicating a hurricane's strength, is not very good at informing the public of all the hazards a hurricane can bring. Most deaths in hurricanes are due to water (either flooding or storm surge), not wind, which is what the SS scale measures. This scale is designed to incorporate more of the other hazards a hurricane can bring into account in order to give the public more balanced information of the total picture, but it is meant to be used in conjunction with the SS scale, not as a replacement. I acknowledge that the scale is very unbalanced at the moment, so bear with me. Suggestions are highly encouraged!


Scoring System:
Generally, hurricanes will be rated on a scale of 1-100, but storms may exceed 100 if they are bad enough. There is no true “cap” to the scale, but there are obvious limits to how high the scale goes. Each category contributes to the overall point total of the hurricane overall. Each category is added together to get a complete max rating for the storm. In addition, I envision graphics that give certain areas risk factors using this system (I envision them looking much like how the SPC's severe weather outlooks appear).

Scale
0-20: [TC1] Mild (mild impacts, minor damage)
20-40: [TC2] Moderate (localized impacts, medium damage)
40-60: [TC3] Damaging (more widespread impacts, somewhat mid-high range damage)
60-80: [TC4] Destructive (widespread destructive impacts, high damage, possible retiring)
80-100: [TC5] Devastating (widespread devastating impacts, devastating damage, likely retiring)
100+: [TC6] Catastrophic (ultra-widespread catastrophic impacts, cataclysmic damage, certain retiring)

Max Rainfall:
If below 3”: Multiply total times 0.5
If between 3” and 10”: Multiply total times 1
If over 10”: Multiply total times 1.5

Wind Speed:
(Max 1-minute Sustained Winds in mph times 0.1) + (1020 - Minimum Storm Pressure in mb times 0.1)

Storm Surge:
Multiply projected storm surge heights in feet by 1, if above 5 ft, multiply by 1.5

Storm Size:
Storm TS Wind Field Diameter in miles multiplied by 0.02

Additional Factors:
These are not the only factors that can contribute to how bad a hurricane is or was. Tornadoes, the explosivity of a storm, and human factors (evacuation problems, levee breaches, etc.) can also contribute. I envision each of these categories adding 0-5 points to the overall total.

I ran some of the numbers with information I could find (estimating in certain cases), so this is how the landfalling storms of 2021 in the Atlantic hurricane season scored on the scale as an example:

TS Claudette: 40.2 (TC3)
TS Danny: 15.6 (TC1)
Hurricane Elsa: 38.3 (TC2)
TS Fred: 36.3 (TC2)
Hurricane Grace 51.8 (TC3)
Hurricane Henri 29.8 (TC2)
Hurricane Ida 79.6 (TC4)
TS Mindy 20 (TC2)
Hurricane Nicholas 48.2 (TC3)


Please comment with feedback!

[SectorZ]

I would like that as an add-on to the current system, as more of a point forecast for a specific area while leaving Saffir-Simpson for a broader overview of a tropical system.

Storm surge is a big problem because it is so ultra-specific to a location, mostly due to the chaotic nature of shorelines where they aren't some straight-line beach in most places. The National Hurricane Center has a model for storm surge for storms making landfall, and I can tell you loading it will damn near run all the ram on your computer to load the animation of it because it is quite data-heavy.

One of the interesting things with your scale is the interplay between rainfall and the other factors. Rainfall takes a back seat to the enormous storms but becomes the headline with weaker storms, especially ones that have drifted inland and find their way into the mountains.

This is a really good thought experiment and concept. Warning systems can always be improved, especially when computer technology is enabling more accurate forecasts, and therefore more refined warning systems that match the increased accuracy.

[1]

Does the scale work in a useful way with things that aren't hurricanes or tropical storms? For example, could a severe thunderstorm in New England get a rating of 8?

[CoreySamson]

Does the scale work in a useful way with things that aren't hurricanes or tropical storms? For example, could a severe thunderstorm in New England get a rating of 8?

No, it doesn't. This is only meant for tropical systems.

[US 89]

Storm surge is a big problem because it is so ultra-specific to a location, mostly due to the chaotic nature of shorelines where they aren't some straight-line beach in most places. The National Hurricane Center has a model for storm surge for storms making landfall, and I can tell you loading it will damn near run all the ram on your computer to load the animation of it because it is quite data-heavy.

The other thing about storm surge is the damage it causes is hugely dependent on local geography, so your scale isn't really comparable in different areas. 10 feet of storm surge will do a whole lot more damage in flat coastal Florida than it will in hilly Bermuda, for example.

[CoreySamson]

Concept graphic time. This map delineates what kinds of impacts the areas marked would see. Green areas would receive TC1-level impacts, yellow areas would receive TC2 impacts, and so forth going up the line. I envision this graphic replacing the cone of uncertainty, as this tracks the extent of impacts, not the storm's center, which is more helpful overall. Someone who sees the graphic from New Orleans would instantly know they are in a TC3 zone and could prepare accordingly. For non-weather aware people, this would be a game changer (most people just want to know the impacts for their town when a hurricane is coming, I've noticed). This map could even be linked with evacuation zones so local officials could have better grounds for mandatory evacuations. This map is a representation of what such a map could look like for a storm like Ida last year.



Thoughts?

[epzik8]

Concept graphic time. This map delineates what kinds of impacts the areas marked would see. Green areas would receive TC1-level impacts, yellow areas would receive TC2 impacts, and so forth going up the line. I envision this graphic replacing the cone of uncertainty, as this tracks the extent of impacts, not the storm's center, which is more helpful overall. Someone who sees the graphic from New Orleans would instantly know they are in a TC3 zone and could prepare accordingly. For non-weather aware people, this would be a game changer (most people just want to know the impacts for their town when a hurricane is coming, I've noticed). This map could even be linked with evacuation zones so local officials could have better grounds for mandatory evacuations. This map is a representation of what such a map could look like for a storm like Ida last year.



Thoughts?

Very tight graphic and explanation, and definitely more advanced than the cone.

[jgb191]

Most deaths in hurricanes are due to water (either flooding or storm surge), not wind, which is what the SS scale measures.

The storm surge does indeed cause the most destruction/fatalities, however the main driver of the hurricane is the central pressure of the system.  A pressure reading close to (almost) 1,000 millibars is a rather weak for a tropical system, whereas a reading closer to 900 millibars makes for one of the most intense storms.  The lower the millibars, the higher the winds.  The higher the winds, the larger the storm surge.  Of course other factors will also determine impact, like how heavily populated the area of landfall is, how many people take the watches/warnings seriously, how efficient are the evacuation routes, elevation of the land area.  Believe it or not, tornadoes are even formed from landfalling hurricanes; those can exacerbate the impact.

Here is my thing with the Triple S as I like to call it: (Saffir-Simpson Scale)  I don't like how the categories are spaced out.  I believe it should be an upgrade for every twenty MPH increments.

C1:  75 - 95 MPH
C2:  95 - 115 MPH
C3:  115 - 135 MPH
C4:  135 - 155 MPH
C5:  155+ MPH

That's how I would have liked it....evenly spaced for easier classification.  Even more, add two more categories:  C6 would be from 155 - 175 MPH and C7 would be from 175 - 195 MPH.

Fun Fact:  Robert Simpson and I share the same home city:  Corpus Christi, Texas.

[SectorZ]

Most deaths in hurricanes are due to water (either flooding or storm surge), not wind, which is what the SS scale measures.

The storm surge does indeed cause the most destruction/fatalities, however the main driver of the hurricane is the central pressure of the system.  A pressure reading close to (almost) 1,000 millibars is a rather weak for a tropical system, whereas a reading closer to 900 millibars makes for one of the most intense storms.  The lower the millibars, the higher the winds.  The higher the winds, the larger the storm surge.  Of course other factors will also determine impact, like how heavily populated the area of landfall is, how many people take the watches/warnings seriously, how efficient are the evacuation routes, elevation of the land area.  Believe it or not, tornadoes are even formed from landfalling hurricanes; those can exacerbate the impact.

Here is my thing with the Triple S as I like to call it: (Saffir-Simpson Scale)  I don't like how the categories are spaced out.  I believe it should be an upgrade for every twenty MPH increments.

C1:  75 - 95 MPH
C2:  95 - 115 MPH
C3:  115 - 135 MPH
C4:  135 - 155 MPH
C5:  155+ MPH

That's how I would have liked it....evenly spaced for easier classification.  Even more, add two more categories:  C6 would be from 155 - 175 MPH and C7 would be from 175 - 195 MPH.

Fun Fact:  Robert Simpson and I share the same home city:  Corpus Christi, Texas.

The winds are spaced out the way they are because those changes in wind speeds start leaping from one level of destruction to another, hence why even their spacing isn't the same from one to another.

This explains well, https://www.nhc.noaa.gov/aboutsshws.php

[jgb191]

^ I see your point, but wind speed isn't necessarily directly proportional to the amount of destruction as was the case in 1999.  Hurricane Bret slammed onto the South Texas coast with 120 MPH winds but since Kenedy County is the most sparsely populated county in the US, the damage was minimal amounting to about only several million dollars, while nearly a month later Hurricane Floyd made landfall in the Carolinas with 105 MPH winds but inflicted several billion dollars in destruction.  The two reasons Floyd was worse than Bret was because the Carolinas coast was more densely populated than South Texas coast, and because you may remember Hurricane Dennis struck the Carolinas a couple of weeks before Floyd did, so it was double trouble for the Carolinas.

[SectorZ]

^ I see your point, but wind speed isn't necessarily directly proportional to the amount of destruction as was the case in 1999.  Hurricane Bret slammed onto the South Texas coast with 120 MPH winds but since Kenedy County is the most sparsely populated county in the US, the damage was minimal amounting to about only several million dollars, while nearly a month later Hurricane Floyd made landfall in the Carolinas with 105 MPH winds but inflicted several billion dollars in destruction.  The two reasons Floyd was worse than Bret was because the Carolinas coast was more densely populated than South Texas coast, and because you may remember Hurricane Dennis struck the Carolinas a couple of weeks before Floyd did, so it was double trouble for the Carolinas.

Noted, but where does your change to the wind speed classifications address this?

[jgb191]

My change really doesn't address this, it just meant for easier classification by a using a simple formula of just adding twenty MPH increments per category.  I wasn't aware of the reasoning behind the current spacing out of each category until you provided the links.  But there are just so many other variables mentioned in earlier posts that ultimately determine damage or destruction.  It's not like the old Fujita-Pearson Scale or now the Enhanced scale used for tornadoes, those scales is based on damage after the event.  The Saffir-Simpson scale measures the hurricane in real time based on maximum sustained wind speed, especially as a warning before the storm slams a coast.

[Scott5114]

Perhaps instead of starting with 1 you could start with 0 and shift everything else down a notch. Then you would end up with a six-tier system, 0-5, which is the same numerical range the Fujita scale uses. You could have them be T0 through T5, for tropical.

You should call it the Severe-Samson Scale.

[jgb191]

^ Sure, one could designate T0 as a tropical wave, then T1 as a tropical Depression, T2 as a tropical Storm, T3 for Category One Hurricane, and so forth.

[US 89]

Ah, but we already have the TORRO scale, which rates tornadoes on a scale from T0 to T11.

If you’re wondering why you’ve never heard of it, it is apparently only used in the UK. It’s like us refusing to adopt the metric system.

[SectorZ]

Ah, but we already have the TORRO scale, which rates tornadoes on a scale from T0 to T11.

If you’re wondering why you’ve never heard of it, it is apparently only used in the UK. It’s like us refusing to adopt the metric system.

I don't know, I may actually like their scale better. It amuses me that I've never heard of it until today, which I guess means I didn't learn much about British meteorology in school.

[Scott5114]

Ah, but we already have the TORRO scale, which rates tornadoes on a scale from T0 to T11.

If you’re wondering why you’ve never heard of it, it is apparently only used in the UK. It’s like us refusing to adopt the metric system.

I don't know, I may actually like their scale better. It amuses me that I've never heard of it until today, which I guess means I didn't learn much about British meteorology in school.

Giving it a once-over, it seems pretty useless. It's basically a warmed-over Beaufort scale (which is itself pretty silly—in the US we just use direct wind speed numbers rather than faffing about with a scale). They say it's better than Fujita because it is a direct wind speed scale and doesn't rely on damage ratings like Fujita does. But tornadoes are so relatively narrow that the odds that any given tornado will directly strike an anemometer are very low (and the odds the anemometer survives long enough to record an accurate wind speed even lower) that, in practice, it functions as a damage scale anyway, just without the defined damage assessment rubric that Fujita is based on. (And British tornadoes are weak enough that the upper reaches of the scale have never been used, so anyone attempting to assign one of them would basically be on their own.)