Category 6 Hurricanes? (Category six Hurricanes?)
Posted by: hurricane in Hurricanes And Tropical Storms, Records, Saffir-Simpson ScaleHurricanes are categorized by several methods, the most well known being the Saffir-Simpson Hurricane Scale. The Saffir-Simpson scale, developed in 1969, is based on the wind speed of the hurricane. The various categories are listed below in their traditional form:
Category 1: 74 to 95 mph
Category 2: 96-110 mph
Category 3: 111-130 mph
Category 4: 131-155 mph
Category 5: greater than or equal to 156 mph
The amount of damage between each category does not increase linearly. Each increase in category greatly increases the damage potential. The original scale included no Category 6 hurricane. Robert Simpson has stated that there was no reason to include an additional category because the damage would be severe no matter the wind speed over 155 mph. Improvements in building engineering over the past roughly 35-40 years may have changed that dynamic and might necessitate the addition of a category 6 hurricane.
In our view, if the Saffir-Simpson scale were adjusted to include another category, it would likely be as follows:
Category 1 hurricane: 74 to 95 mph
Category 2 hurricane: 96-110 mph
Category 3 hurricane: 111-130 mph
Category 4 hurricane: 131-155 mph
Category 5 hurricane: 156-175 mph
Category 6 hurricane: greater than or equal to 176 mph
The current Saffir-Simpson scale has the following wind speed bands for its categories:
Category 1: 21 mph band
Category 2: 14 mph band
Category 3: 19 mph band
Category 4: 24 mph band
Category 5: unlimited band since there is no upper limit besides atmospheric limitations
A Category 5 band would likely be a 19 or 24 mph band and therefore a category 6 hurricane would have winds greater than or equal to 176 mph (or 181 mph). The 176 mph figure seems to make the most sense based on wind speeds and engineering.
On a related note, the question has come about, what about a storm that has winds of 95.5 mph or 110.5 mph or 131.5 mph or 155.5 mph etc? It would seem that the scale does not provide for those wind speeds. A continuous mathematical restatement of the Saffir-Simpson Scale should be made with the addition of an additional category.
The Saffir-Simpson scale should be restated as:
Category 1 Hurricane: 74 to 95 mph
Category 2 Hurricane: > 95 to 110 mph
Category 3 Hurricane: > 110 to 130 mph
Category 4 Hurricane: > 130 to 155 mph
Category 5 Hurricane: greater than 155 mph
Or, alternatively:
Category 1 Hurricane: 74 to less than 96 mph
Category 2 Hurricane: 96 mph to less than 111 mph
Category 3 Hurricane: 111 mph to less than 131 mph
Category 4 Hurricane: 131 mph to less than 156 mph
Category 5 Hurricane: 156 mph or greater
Or with an additional category:
Category 5 Hurricane: >155 to less than 175 mph
Category 6 Hurricane: 175 mph or greater
or
Category 5 Hurricane: 156 mph to less than 176 mph
Category 6 Hurricane: 176 mph or greater
Precision is important in the sciences and hurricane forecasting is nothing if not a science. Likewise taxonomies assist in the classification and therefore the study of any phenomenon. Our view is that the Saffir-Simpson scale has a few minor areas that need correction.
For more information on the Saffir-Simpson scale, see this page.
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December 4th, 2008 at 9:43 pm
if you look at the pattern of the upper limits for wind you see:
110-95 = 15
130-110 = 20
155-130 = 25
if this pattern continues a cat 5 would end at 185 mph
also if you look at pressure:
980-965 = 15
965-945 = 20
945-920 = 25
this would mean a category 5 would end at 890
I haven’t found a pattern to surge but if you look at wikipedia’s data from 2005 Wilma was just on the brink of breaking both these upper bounds this shows that if the pattern continues on the scale that we have a need for a category 6 . I’ve tried extending these patterns as far as possible and found that the scale with this pattern can be extended to category 18. ouch.
December 4th, 2008 at 10:06 pm
if continued this pattern would go like this:
winds(max) pressure(min)
95 980
110 965
130 945
155 920
185 890
220 855
260 815
305 770
355 720
410 665
470 605
535 540
605 470
680 395
760 315
845 230
935 140
1030 45
of course I also found a pattern like this in the non-enhanced Fujita scale maybe it’s time to enhance the Saffir-Simpson scale ?
December 5th, 2008 at 7:07 pm
also if this pattern held up typhoon tip would be a cat 6 on the Saffir-Simpson scale