In fact, it causes 90% of the loss of lives

related to powerful storms.

But when meteorologists talk about a Category 3 system

headed their way, that classification

just takes wind speed into account.

There's no single scale to indicate

both how strong and how wet the systems are.

In general, we tell people in the meteorological community

to hide from the wind, but run from the water.

But if we know water can actually cause more damage,

why haven't we updated the way we measure hurricanes?

Let's take a look back.

The Saffir-Simpson scale, going from 1 to 5,

measures the speed of sustained winds of a hurricane.

It was developed in the 1970s to calculate

how much wind can impact property.

A storm becomes a Category 1 hurricane

when winds reach 74 miles per hour.

This kind of speed can damage roofs,

sidings, and knock large branches out of trees.

Major hurricanes start at Category 3

once winds increase to 111 miles per hour.

They can cause devastating destruction

to well-constructed buildings.

And there's a high chance of injury or death.

Category 5 hurricanes have winds over 157 miles per hour,

and are the top of the scale.

These systems can devastate large areas,

leaving them uninhabitable for months.

But again, this is just from the winds.

It doesn't take into consideration

the impacts of storm surge and rain.

Storm surge happens when winds push water from the sea

onto the land, flooding large areas.

It's fast, powerful, and can send 10 to 20 feet of water

several miles inland from the coast.

Hurricane Katrina was one of the deadliest storms

to ever hit the mainland United States.

But its 127 miles per hour winds

meant it was only classified as a Category 3

when it made landfall in Louisiana.

The water broke the levies protecting New Orleans.

And within a day, about 80% of the city was underwater.

With Hurricane Katrina in 2005,

we really didn't, we didn't have in the collective

public mindset the difference between a really large

powerful storm and a compact powerful storm.

The pictures and the memories of Katrina

aren't really about the wind damage.

It's mostly about the storm surge,

the levies failing in New Orleans, things like that.

And even smaller Category 1 systems

like Hurricane Dolly, which slammed South Texas in 2008,

can leave behind death and destruction for the same reason.

For a while, the Saffir-Simpson Scale

also categorized storm surge,

but it became difficult to communicate

the specific dangers of each storm to the public

since the threats from water and wind can be so different.

So in 2017, NOAA's National Hurricane Center

started issuing official storm surge watches and warnings.

What's different about the storm surge warning

is what's different about the storm surge.

It can occur in somewhat different locations

than the strongest wind, and at different times.

These advisories are key to helping people prepare,

even if they're not directly in the path of a storm.

But they still leave out potential flooding

that could be caused by rainfall,

which is a whole other advisory from NOAA.

You need to know if your location's going to be

impacted by storm surge, or potentially freshwater flooding

that occurs from incredible rainfall amounts.

Because the time to evacuate, or whatever,

isn't when the water is rising into your home,

or business. It's beforehand.

The Saffir-Simpson scale's historical popularity

and basic 1-to-5 format

means it's unlikely to go away anytime soon.

But there are a few alternatives out there,

like the Hurricane Severity Index, owned by StormGeo,

a private weather intelligence company.

It uses a 50-point scale that measures

the size of a hurricane and the intensity of its winds.

Each component gets 25 points, to be more precise.

Size is very important because it matters

for the aerial extent of the impact,

how much time a hurricane's going to hit you.

Things like storm surge, wave heights,

rain amounts are greater.

The HSI can also help people compare storms

they might have already experienced

to get an idea of what to expect.

The index would have placed Katrina's damage potential

in line with a Category 5.

While its intensity was only 13 out of 25,

its size was a 23 out of 25.

But media outlets rarely use the index as a tool,

relying mostly on the Saffir-Simpson scale.

Most journalists include NOAA's storm surge advisories

in their reports as well.

But most of the attention around a storm

still seems to center on the category it falls under.

Atlantic hurricane season goes from

June 1 to November 30.

And 2020 has been a particularly active one.

With things like climate change and a warming world,

hurricanes are more, there's going to be

more intense hurricanes making landfall.

NOAA predicted 19 to 25 named storms.

And as of September 21, we've already had 23.

That's already beaten last year's 18 named storms,

which was also above average.

And even as weather forecasting has been

refined and improved, experts say there's no substitute

for always being ready for a storm to hit.

We have to make sure everybody understands

that the forecasts aren't perfect.

And sometimes the storm does something

not quite what we forecast,

and you really need to be prepared.

Most importantly, follow the advice

of your local emergency management officials.