We need an updated Hurricane “Category 6″ for Houston and Southeast Texas

And the rest of the Atlantic and Pacific basins

CREDIT: National Hurricane Center/NOAA

The cover photo for today is 2015′s Hurricane Patricia in the eastern Pacific--a MEGA-STORM reaching 215 mph winds before weakening and still slamming into central Mexico with 150 mph winds (Category 4).

MEGA-STORM meaning what?

By most standards, a hurricane or typhoon well above the minimum Category 5 wind strength of 157mph... and clearly, 215 mph is WAY above that.

I put together a table below of the hurricane categories and the different wind speed ranges according to the standard Saffir-Simpson scale. You can see that the categories increase with increasing wind speeds:

CREDIT: KPRC2 Storm Tracker Team

Those wind speed increases are anywhere from 14 mph to 26 mph. A Mega-Storm like Hurricane Patricia at 215 mph had winds some 58 mph above the minimum Cat 5 threshold! That’s why you see that 6?

Granted, Patricia is the strongest recorded hurricane in the world, but do we need to add another wind speed category? After all, the strongest Atlantic hurricanes on record range from 175 mph top winds (eg. Camille, Katrina, Andrew) to 185-190 mph winds (eg. Wilma, Dorian, Allen). We’ve seen a good share of Cat 5′s topping out close to the max.

However, given stronger storms in the future, adding another category isn’t so simple, although a recent article turned to Michael Wehner of the Lawrence Berkley National Laboratory who suggests the time has come.

“There haven’t been any (Mega-storms) in the Atlantic or the Gulf of Mexico yet but they have conditions conducive to a Category 6, it’s just luck that there hasn’t been one yet,” said Wehner.

Those “conditions” are due to a warmer world -- more heat in the ocean and more warm moisture in the air increases the intensity of hurricanes.

“Our main purpose is to raise awareness that climate change is affecting the most intense storms,” he said.

To that end, morning KPRC 2 Meteorologist Anthony Yanez asked the current National Hurricane Center director, Michael Brennan, about this idea and he isn’t rushing into it:

“At NHC, we’ve tried to steer the focus toward the individual hazards, which include storm surge, wind, rainfall, tornadoes and rip currents, instead of the particular category of the storm, which only provides information about the hazard from wind. Category 5 on the Saffir-Simpson scale already captures “Catastrophic Damage” from wind, so it’s not clear that there would be a need for another category even if storms were to get stronger. In addition, most deaths in tropical cyclones occur not from the wind but from water - storm surge, rainfall/inland flooding, and hazardous surf - causing about 90 percent of tropical cyclone deaths in the United States. So, we don’t want to over-emphasize the wind hazard by placing too much emphasis on the category.”

I certainly respect the director’s take on this. Saying that, wind drives surge and surge drives surf and the wind drives the moisture inland and wind differences create tornadoes. Without the wind, there isn’t a hurricane. From a social science point of view, we are accustomed to categories whether we are talking about the EF-Tornado scale (a number scale) or risks of Severe Weather based on colors of green, yellow, red, orange. Categories, indeed, raise our awareness.

In addition, the original Saffir-Simpson scale was created in 1971 based on what we could measure and what we could know. Fifty years later, we can measure more and we know more. Adding a Category recognizes that.

What would a Saffir Simpson scale with a Cat 6 look like? Not much different, actually:

CREDIT: KPRC2 Storm Team

One final but important note: the National Hurricane Center already publishes a Hurricane Damage Potential chart which is FULL of numbers so I can show you in two parts below and then explain.

CREDIT: NOAA
CREDIT: NOAA

This chart illustrates that taking into account the winds, surge, rain, flooding and tornado potential (the whole nine yards, so to speak) a Category 1 storm of 75 mph represents baseline damage while a Category 1 storm of 95 mph would cause 6.6 times more damage. If you compare that same Cat 1/75mph storm to a Category 4 storm of 150 mph then the damage increases 256 times! Even higher, this scale does go to 190 mph with a 1,696x more destructive potential than 75 mph. Obviously, this chart emphasizes that higher wind speeds increase the damage potential significantly so I would suggest, again, that recognizing the wind is top priority. The chart above stops at 190 mph. Why are we stopping at 190 mph when Hurricane Patricia topped out at 215 mph?

Frank

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About the Author:

KPRC 2's chief meteorologist with four decades of experience forecasting Houston's weather.