Is It Time To Establish A Category 6 For Hurricanes?

Satellite image of Category 5 Hurricane Melissa last month.
It was such a powerful storm that it is once
again raising the question of whether there should
be a new Category 6 for extra powerful hurricanes.

After the power of Hurricane Melissa, the question of whether to create a Category 6 ranking for hurricanes is being raised again. 

Melissa was part of a spate of Atlantic hurricanes that were much more powerful than most past storms. 

Climate change might be making some hurricanes stronger than ever before, even though the overall number of such storms doesn't seem to be increasing.  

Hurricane strength is determined by the Saffir-Simpson Hurricane Scale.  It's a five-point scale, with the worst hurricanes being Category 5, with winds of 157 mph or more. 

On that scale, the difference in wind speed between the categories of hurricanes is around 30 mph, give or take. For instance, a top range Category 4 hurricane has winds 27 mph stronger than a top-tiered Category 2 hurricane. 

The peak winds in Category 5 Hurricane Melissa were 185 mph, or 28 mph above the threshold for that category. 

With hurricanes likely getting stronger and stronger amid climate change, will hurricanes need a Category 6? And how would that work?

Meteorologists and other scientists are beginning to grapple with the question.  

According to The Independent:

"It's been proposed that such a hurricane would have maximum sustained winds of 192 miles per hour and could do much more damage than structures designed to withstand Category 5 winds are able to handle."

Hurricane Melissa came close to this theoretical Category 6, falling just 7 mph under that proposed category. Post-storm analysis might boost Melissa's top winds to or over 192 mph, because there is some uncertain, preliminary evidence that winds might have been higher than first reported.

Meteorologists are divided on the issue. 

Certainly, some support the idea of creating a Category 6.

"As long as we're using wind-based metrics, it simply doesn't make sense (mathematically or fiscally or sociologically) to artificially cap the scale at 5 any more," said Climatologist Michael Mann.

Katharine Heyhoe, an atmospheric scientist and Chief Scientist at the Nature Conservancy, told the Independent that a Category 6 would take into account the worrisome effects of climate change and the bigger risk of damage from worsening storms. 

Heyhoe said the whole Saffir-Simpson scale might need a full redesign to take into account rainfall amounts associated with hurricanes. Flooding is responsible for a majority of the hurricane-related economic impacts.

On the other hand, Phil Klotzbach, an atmospheric scientist and hurricane expert at Colorado State University, said a Category 6 is unnecessary. Category 5 storms can leave communities uninhabitable for weeks or months, so the effects of a supposed Category 6 would have little practical difference. 

Another problem with fudging with the Saffir-Simpson scale is it would make it hard to compare storms decades ago with ones that occur under a scoring system with a Category 6.

"If we change it, it becomes difficult to compare new storms to old ones unless we reanalyze past data. We'd be moving the goalposts for what defines a 'major' hurricane," said Dr. Zachary Handlos, director of Atmospheric and Oceanic Sciences Undergraduate Degree Program at Georgia Tech, in an interview with WCNC.

However, Handlos said it could still be worth it to establish a new classification system for hurricanes. The Saffir-Simpson scale only takes into account wind speeds. 

Which means the scale doesn't capture a hurricane's a storm's full impact.  Hurricanes cause severe inland flooding storm surges and tornadoes, all of which can devastate towns and cities far from where the hurricane came ashore. 

Hurricane Helene last year is a classic example of that. It came ashore in Florida but destroyed swaths of western North Carolina. 

Storm surges and rainfall cause almost 80 percent of hurricane deaths, which is a good reason to revamp the hurricane categorizing system. 

Handlos said a new hurricane rating system should be easy enough for the public to understand. They need to know right away whether they should evacuate, whether they're allowed to drive through the immediate aftermath of a hurricane, how big the flooding threat is, that type of thing. 

There already is an alternative hurricane rating system. 

As Live Science reports, Jennifer Collins, a professor in the School in Geosciences at the University, and her colleagues developed the hurricane rating system called TCSS taking into account wind speed, storm surge and rainfall. 

Collins' hurricane rating system scores between one and five each of the three hazards, depending on their predicted severity for a given hurricane. The scores are combined into a final score. 

Collins' research team sent 4,000 participants living along the Gulf and East coasts forecasts for 10 fictitious hurricanes affecting their communities.

Half the participants received warnings based on the Saffir-Simpson scale, while the other half got her  TCSS system. The participants then filled out an online quiz about how they would react under the different scenarios. 

It turns out people who received the TCSS forecasts were more likely to identify the main hazard from a hurricane correctly, and significantly more likely to evacuate for non-wind hazards than if they had received the Saffir-Simpson rating. 

The survey participants also were more likely to take the correct precautions, such as setting out sandbags, or put up window protections with Collins' warning system. 

As we noted, hurricanes are not just about wind. Some hurricanes have relatively weak winds, but incredible amounts of rain. (Think Hurricane Irene, which affected Vermont in 2011).

The trick is to make a warning system that acknowledges the complexity of the storm, but at the same time keeps things simple so that the public knows how to react to the hurricane.  

Deadly Texas Tornado Seemed More Chaotic Than Most

Image from Val and Amy Castors' live stream as they
drove in Matador, Texas immediately after a 
powerful tornado passed through. 

 Maybe it's because of the wide availability of immediate social media images, but the tragic tornado that struck the small town of Matador, Texas seemed especially chaotic and scary. 

The tiny town of about 570 residents was slammed Wednesday by a huge tornado coming in from the north. The storm killed four residents and left 10 others injured. Most of the western half of Matador was leveled.

The twister was wrapped with a thick curtain of torrential rain and hail, making the whole thing seem especially apocalyptic. 

The National Weather Service office in Lubbock, Texas said the parent thunderstorm developed explosively north of Matador and soon produced the tornado that trashed the town. A post-storm investigation revealed the tornado was a strong EF-3 with top winds of 165 mph.

The tornado was about a quarter mile wide and traveled 9.4 miles. Honestly, it was just badly located. 

The tornado had to be intense. The engine of a car was torn out of the vehicle and entire houses and buildings were leveled. Grass was scoured out of fields.

As a side note, I'm a little perplexed by whether people on Twitter upset and angry that the Matador tornado didn't get a higher rating.  Tornadoes are rated from EF-0 to EF-5, with EF-5 being the most intense -and rare.

The critics say they think the damage warranted an EF-4 or EF-5.  But the National Weather Service office in Lubbock worked with Texas Tech University National Wind Institute to estimate tornado wind speed based on structure damage in Matador. 

Of course, the rating doesn't really matter to the people in Matador who had to deal with the twister. 

 Adding to the chaos was large hail that accompanied the huge storm. Hailstones were as large as 4.5 inches in diameter, or about the size of a grapefruit. 

Video taken just as the tornado was leaving Matador appeared to show breaks in the clouds and winds and rain diminishing. That's pretty common in the moments immediately after a tornado passes.

But that was only a very brief interlude. Within perhaps two minutes, another supercell thunderstorm  intense hail and blinding, wind driven rain arrived just as rescuers began attempts to pull people from the wreckage. That turn of events is rather unusual and made the aftermath all the more hellish.

The second storm finally left Matador around 10 p.m, around two agonizing hours after the tornado hit. 

 Large tornadoes are common in the Texas Panhandle, but it's rare for two twisters within a month, never mind a week, to cause deaths in the region. 

A twister hit Perryton, Texas on June 15, killing three people and injuring about 50 others. 

The four deaths in Matador were the most from a single Texas tornado since 2015.

The Texas Panhandle has vast tracts of open land sparsely dotted by small towns and two larger cities, Amarillo and Lubbock.   t's very easy for a tornado to travel ten miles in the Texas panhandle without hitting anything important. So the Matador tornado was very bad luck. 

This isn't the first time a destructive tornado marauded through Matador. A twister in May, 1984 destroyed about 30 homes in Matador. 

Video: KWTV storm chasers followed the tornado into Matador, and were stunned to see the damage when they arrived in town. Very dramatic video. Click on this link to view, or if you see the image below, click on that: