Measuring hurricanes hard when gauges go down, as they did during Irma

As Hurricane Irma bullied ashore, walloping the Florida Keys and blitzing the southeast coast, the nation’s primary weather gauges tasked with measuring the rampage went dark.

Either complete failure, or loss of multiple functions, occurred at eight sights monitored by the National Weather Service office in Miami. The two official gauges-of-record in the Keys also died during the storm. And the Melbourne station, which was waiting for a part when Irma struck, failed to collect wind speeds on Sept. 10 and 11.

A lone official South Florida station withstood Irma’s blow, which for the majority of the region north of the Keys did not include sustained hurricane-force winds.

“Palm Beach International Airport is the only one that stayed up and recorded a full set of data all the way through,” said Robert Molleda, warning coordination meteorologist for the NWS in Miami.

RELATED: Read all of The Palm Beach Post’s Hurricane Irma coverage

While the weather service can cobble together storm stats from other devices, including home weather stations and private companies, former NOAA scientists and university storm researchers said the federal government should fortify its measurement sites to withstand one of Mother Nature’s most studied creations.

In many areas, including West Palm Beach, the gauges — part of the Automated Surface Observing System (ASOS) — are the official climate record. When a station goes down in a hurricane, meteorologists note the last measurement made and mark the record as “incomplete.”

“That’s a big deal,” said Mark Powell, a veteran of the National Oceanic and Atmospheric Administration’s Hurricane Research Division and a storm expert with Tallahassee-based Risk Management Solutions. “Those measurements are critical.”

We need reliable information

Powell studied why anemometers failed during 1992’s Hurricane Andrew and the implications of not having reliable wind information after a storm.

Not only is the weather data key for modeling future storms and verifying forecasts, they’re a tool used by insurance companies to establish risk and pricing.

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For emergency managers, having accurate wind speeds are vital to rumor control, and can help with future evacuations. Often, people believe they have survived a storm with winds much worse than what actually occurred, which can influence their decision on whether to evacuate in the future.

“This information serves all interests during and following an event, and helps answer the most basic questions like ‘what really happened,’” said John Schroeder, a professor of atmospheric science at Texas Tech University. “It also contributes to much more detailed science and engineering agendas.”

After 2005’s Hurricane Wilma, some Palm Beach County residents found it hard to believe the destructive cyclone was just a Category 2 when it entered Palm Beach County from the west. After all, it knocked out power for weeks, tossed hundreds of railroad cars off their tracks, and ripped roofs off homes from the Glades to the coast.

LIVE WEATHER: Download the Palm Beach Post WeatherPlus app here

But a January 2006 National Hurricane Center report found sustained-wind measurements of just 78 mph in Belle Glade, equivalent to a low Category 1, and a mere 61 mph in Clewiston, not even enough to be considered a hurricane.

The hurricane center acknowledged at the time that its data was marked by large gaps, partly because wind gauges stopped reporting data after losing power. The data also came from a hodgepodge of agencies and companies, some of which might not meet the hurricane centers’ specifications for wind-gauge height or definition of sustained winds.

“We as a country should make a commitment to actually measure what the winds are in hurricanes,” said Hugh Willoughby, a distinguished research professor at Florida International University and former director of NOAA’s Hurricane Research Division. “Lets get backup power and design them to withstand a storm. It can make a big difference.”

Lack of hard numbers because of damage

Days after Irma, Willoughby said he heard “second hand” that there were not sustained hurricane-force winds in Miami-Dade County, but lamented the lack of hard numbers from official sites. After an analysis of other gauges, the National Weather Service found Fisher Island and the Fowey Rocks lighthouse just east of Biscayne Bay felt sustained winds that reached 74 mph and 81 mph, just meeting the threshold for a Category 1 hurricane

In the central Florida Keys, where Category 4 Irma made landfall at 9:10 a.m. Sept. 10, the last measurement from the gauge at the Florida Keys-Marathon International Airport was taken Sept. 9 at about 8 p.m.

AFTER IRMA: Florida still vulnerable to October storms

It registered 71 mph wind gusts – not even Category 1. But Jon Rizzo, acting meteorologist in charge at the NWS in Key West, said the amount of damage suggests gusts of up to 130 mph in nearby Big Pine Key.

Isolated areas on Big Pine Key may have experienced gusts as high as 160 mph, Rizzo said. The strongest gust recorded by a gauge in the Keys during Irma – 120 mph — was from a weather station at a private residence and one maintained by the Department of the Interior.

“While we do have a bit of a blind spot where the core of the storm went through and where conditions were most severe, there were opportunities to get a feel for winds in Key West proper and afterwards by the damage survey,” Rizzo said.

The gauge at the Key West International Airport recorded a peak gust of 94 mph at about 7:15 a.m. Sept. 10, but observations cut off when power was lost.

The official ASOS gauges are a joint effort between the National Weather Service, Federal Aviation Administration, and the Department of Defense.

Why gauges are important

There are about 1,000 ASOS sites nationwide, which are often placed at airports to provide weather reports to pilots and record details on sky condition, wind speeds, sea-level pressure and rain amounts.

There are two primary reasons why gauges fail; when the electricity goes out or when they stop communicating data because of a processing problem. If live communications stop, but electricity remains, the gauge will keep a 12-hour record.

Mark Miller, director of the surface and upper air division at NOAA’s Office of Observations, said after 2005’s Hurricane Katrina there was a push to update ASOS gauges with generators.

About 100 gauges were upgraded, including 14 in Florida. Miller did not know where those gauges were located.

But another problem, Miller said, is the aging processors that relay and record the weather data.

“That capability is really old, about a couple decades,” Miller said. “Once we can upgrade that processing, the on-board storage will also be updated.”

Instead of 12 hours of data, as much as a month of observations may be retained. That effort is expected to begin in 2019 as part of the Service Life Extension Program.

“I think taxpayers’ money would be well served in hardening our national network so when we have events that cause many billions of dollars in damage, we have accurate information,” Powell said. “They just have to make it a big enough priority.”

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