Many people misunderstand this famous hurricane forecast graphic. It can be a deadly mistake.
The National Hurricane Center has addressed criticism of the "cone of uncertainty" graphic, which some leaders misread as Ian took aim at Florida.
As Hurricane Ian zeroed in on Florida, the National Hurricane Center's track forecast graphic fluctuated along the coast as specialists tried to pin down Ian's ultimate destination.
Over three days, the center of the famous "cone of uncertainty" hovered over Tampa Bay, shifted north as far as the Big Bend, then dropped back over Tampa Bay. But on the day before landfall, it moved continually south, homing in on barrier islands off the Lee County coast.
The islands were always in or at the edge of the forecast cone, but experts say it appeared some residents and officials missed that key point, delaying critical decisions while focusing on a possible Tampa landfall.
That ignited controversy over the cone and prompted calls for a replacement. The hurricane center addressed that confusion and criticism this week.
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Ian walloped the Southwest Florida coast on Sept. 28 with a storm surge of up to 15 feet, winds of 150 mph or more and up to 14 inches of rain. At least 109 people died. Where Ian made landfall in Lee County, at least 54 died, including at least 32 who drowned.
The many deaths and thousands of water rescues across the state prompted several experts to question whether it might be time to try something new. Too many people misunderstand the graphics, including local and state officials, they said. A Lee County official, Gov. Ron DeSantis and a Federal Emergency Management Agency official all were quoted saying Lee County wasn’t in the cone at 72 hours before landfall.
In a response Monday, Jamie Rhome, the hurricane center's acting director, said Ian's center stayed within or on the edge of the cone throughout the entire forecast.
So how can similar confusion be prevented?
What is 'the cone of uncertainty'?
The cone communicates the most likely track of the center – or eye – of the storm. It is made up of a series of connecting circles, one for each time frame in the forecast.
Together, the circles become a cone – narrow at first and much wider as the forecast progresses.
Each of the cone's circles use 67% of the center’s forecast errors over the previous five years. For this season, the resulting window is less than 39 nautical miles in any direction at 24 hours out, 67 nautical miles at 48 hours and 100 nautical miles at 72 hours.
It turns out the entire 5-day track stays within the cone about two-thirds of the time, said James Franklin, one of the center's retired hurricane specialists. But there’s always a chance the center of the storm could be outside the circles or even outside the cone, influenced by such factors as how slow or fast the storm is moving.
The circles are based on errors that can occur in any direction, something people often misunderstand, he said. Storms still make unexpected shifts in speed or track.
Franklin finds it surprising people make decisions assuming the forecast is going to be pretty close to perfect, he said. “Haven’t people seen enough changes in the forecast, or storms that don’t do what’s expected to keep making that particular mistake?"
He was one of several to say even though the cone will always be needed, it might be time to shift the focus to potential hazards.
National Hurricane Center responds to Ian forecast confusion
People tend to rely on the cone because it’s simple and familiar, but also tend to make assumptions, “sometimes subconsciously, about what it means," Rhome said. His comments were released Monday as a question-and-answer conversation in response to questions about the use of the cone graphic in forecasts.
The center is “absolutely” open to evolving its communication to be more effective, he said. He pointed out they've worked with the National Weather Service, National Oceanic and Atmospheric Administration and social scientists for more than a decade to improve graphics and messaging, including the forecast cone.
Ian's track forecast cone:Were forecasts for Hurricane Ian wrong? What experts say about the 'cone of uncertainty.'
Communicating a hurricane's potential impacts is more complex than just the cone, Rhome said. That’s why the center has added new products, such as graphics to convey the risks of storm surge and publishing key messages with the cone graphic.
The challenge is not everyone has the time, bandwidth or desire to sift through all the information the center provides, he said. Including all the hazards in one cone would be too "cluttered" to be useful, but he doesn't think the cone will ever go completely away.
Many people misunderstand 'the cone of uncertainty'
Earlier this year, the American Meteorological Society published a study by a group of University of Miami researchers who surveyed more than 2,800 people about their understanding of the cone.
Its results suggest a “rethink” on how to communicate uncertainty, size and areas of likely damage, said the authors, who are working with the hurricane center. People had difficulty understanding the cone graphic and frequently misinterpreted the messaging. Only 18% of their respondents correctly answered all five of their questions about the forecast cone graphic.
The graphic is a valuable visualization, said author Barbara Millet, assistant professor in the university's school of communication. "But it is not one size fits all."
Some people mistakenly feel safer in locations just outside of the cone boundaries, for example, or believe there's no risk beyond the cone, she said. She added it may be that the cone graphic does not convey the information the public needs to make decisions about protective actions.
How can hurricane forecast confusion be lessened?
Millet said moving toward a personalized approach, providing residents with tailored information, may reduce confusion.
The emphasis needs to be on impacts rather than storm tracks, said Craig Fugate, former chief of both FEMA and Florida’s state emergency management division.
Fugate heard the public and officials who mistakenly thought the storm was headed to Tampa Bay, he told USA TODAY in an email. “But if you read both the National Hurricane Center statements, storm surge watch and warn areas, and the local NWS Office in Tampa products, they were communicating uncertainty in the track, but that this was also a large storm with potentially deadly impacts along the SW Florida coast.”
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Bryan Norcross, a FOX Weather hurricane specialist, initially tweeted it might be time to consider "ditching the forecast cone." But, he later told USA TODAY a simple solution may be widening the cone to encompass more of the potential errors.
The real problem is people look at the cone and nothing else, Norcross said. They need to “stop looking at the cone once watches and warnings come out and focus on those instead.”
“The cone has acquired an outsized influence in modern hurricane communications,” he wrote in a Facebook post.
People at all levels of government are trained by the hurricane center to interpret its forecast products, Norcross wrote. “It was and is shocking to hear leaders ranging from the Governor of Florida to the head of FEMA be misled by the cone,” he said.
NOAA social scientist Gina Eosco said more research is needed into the cone and people’s perceptions of it before it's ditched. “Before we replace anything, it is important to reflect on why it exists at all,” she said. “The purpose of the cone is to convey the track uncertainty. When a storm is over the open Atlantic, the cone is a critical piece of information, as impacts to land are unknown at that time.
“The truth is that we know very little about people's changing risk perceptions during an evolving hurricane. Until we know more about how people receive, perceive and take protective action on our forecasts, we don't know what to change about the forecast communication.”
The hurricane center will carefully analyze its forecast and the warning process in the coming weeks, as it does after every storm, Rhome said.
Whatever shape the graphics ultimately take, something new needs to happen, Norcross wrote. “Scores of people died. We can only honor them by finding a new paradigm that doesn't result in critical misconceptions by so many decision-makers.”