Why storms like Dorian suggest we need a new way of measuring hurricanes

The nature of storms is changing — and at least one meteorologist says it's time to change the way we measure them.

This week, Hurricane Dorian blew past expectations, devastating the Bahamas and raking the coast of the Southeastern U.S. It became the most damaging storm to ever hit the island nation and left 70,000 people in need of immediate humanitarian relief. At peak strength, Dorian reached Category 5 status, the most severe designation. 

Jeff Masters, who's been a meteorologist for almost 40 years, wonders whether the Saffir-Simpson Hurricane Wind Scale accurately conveyed the destruction Dorian was capable of inflicting. Masters, who has kept a close eye on the evolution of natural disasters throughout his career, argues that the scale could be doing more harm than good as storms become more frequent and severe. 

"[There's been] a really noticeable upsurge in these sort of catastrophic, almost Category 6 storms," he told Day 6 host Brent Bambury.

"A low-end Category 5 with 160 mile-an-hour winds has 60 per cent less destructive power than Dorian had … So yeah, it might be good to include an extra notch on the scale to show that 'Hey, these sorts of extreme storms are going to do a lot more damage.'"

What exactly does the Saffir-Simpson Hurricane Wind Scale measure? Is it enough?

Hurricane damage is caused by three forces: storm surge, heavy rains and extreme wind. The Saffir-Simpson scale measures sustained wind speed and potential property damage. 

According to the National Hurricane Centre, a Category 1 hurricane would have sustained winds of at least 119 km/h. A Category 3, beginning at 178 km/h, is the point at which the storm is considered "major" and the damage is estimated to be devastating to catastrophic. 

"You really need to have three separate scales, or maybe you need to have a colour-coded danger scale for all of these factors taken together," Masters argued, citing the fatal impact of hurricane flooding in storms that don't surpass the first or second category. 

"We've seen time and time again when a hurricane that has a relatively low rating on the wind scale, say Category 1 or 2, when it comes ashore, people don't take it seriously," he said, drawing on the example of 2012's Hurricane Sandy.

"It brought a record storm surge that flooded hundreds of miles of coast. And people weren't taking it seriously."

Should we introduce a wider scale to account for the changing nature of storms?

Masters said he isn't satisfied with the system in place when it comes to educating the public about a hurricane's potential danger. 

"We can do better. We've seen a lot of cases where people don't act on the messages we give them," he said. 

"In Europe they use scales where they talk about yellow alert, orange alert and red alert. And they very rarely use the red alert. So something like that might work."

Where are these "mega hurricanes" coming from? 

Ocean temperatures have been rising at an accelerated, record-breaking rate, and the energy that drives hurricanes is drawn from the warmth of the water, Masters said. Warming waters have been met with faster winds, which cause more extreme damage, he continued. 

"We can anticipate as the decades come, we're going to see a sharp increase in these sort of mega-hurricanes projecting out into this century."

To hear the full interview with Jeff Masters, download our podcast or click 'Listen' above.