April 7, 2013

Use of impact-based severe weather warnings expanding this year

The impact-based warnings tested in a handful of National Weather Service branches last year — including Wichita — are going to be used in all or parts of 17 states in the Great Lakes and Northern Plains regions, officials said.

The impact-based warnings tested in a handful of National Weather Service branches last year — including Wichita — are going to be used in all or parts of 17 states in the Great Lakes and Northern Plains regions, officials said.

Expanded use of the new warnings will be used by the 38 branches that make up the agency’s central region. The warnings are sent to emergency managers and media for use in warning residents about threatening storms. The warnings also are posted on the National Weather Service’s website.

Instead of describing a storm’s strength, the warnings focus on the damage they could do and the potential impact on lives.

“Major house and building damage likely and complete destruction possible,” a tornado warning issued late in the evening of April 14 for south-central Kansas read. “Numerous trees snapped. Major power outages in path of tornado highly likely. Some roads possibly blocked by tornado debris. Complete destruction of vehicles likely.”

Officials credited such warnings with helping to prevent fatalities during a major tornado outbreak across Kansas last April 14, including a strong tornado that struck Oaklawn, Haysville and part of southeast Wichita after sunset.

“This is a service we hope to never use,” said Michael Hudson, chief operations officer for the weather service’s central region headquarters in Kansas City, Mo.

The warning system going into effect is “nearly identical” to the pilot project tested last year, officials said.

The warnings are intended to more clearly describe the threat and potential impact severe storms pose so residents can quickly make informed decisions about taking shelter. “We learned that the emergency managers liked the extra information that was in the warnings – the information that got to the magnitude of the weather,” Hudson said.

Interviews with emergency managers and broadcast meteorologists in central Kansas revealed that the warnings on the day of the tornado outbreak were a vital culmination to the buildup in the days prior to April 14, Hudson said. Weather officials had been warning of the violent weather threat in the days leading up to then.

“The warnings completed that messaging,” Hudson said.

“That last message ... where you’re hearing things like ‘catastrophic’ and ‘You could be killed if you’re not underground’ paint a picture,” he said.

A tornado warning issued for Russell County on the afternoon of April 14 cautioned “significant house and building damage possible. Mobile homes completely destroyed if hit. Some trees uprooted or snapped. Vehicles will likely be thrown by tornadic winds.”

The April 14 outbreak included 24 tornadoes that touched down in Kansas. Tornadoes were on the ground in Kansas for more than five hours, and their paths covered nearly 200 miles, according to research conducted by the weather service.

Tornadoes were reported across four states that day. Six people were killed in Woodward, Okla.

“Those are the types of days that we really have impact-based warnings for,” Hudson said. “These are really exceptional days.”

The response by residents of Sedgwick County to the dangerous weather on April 14 convinced Sedgwick County Emergency Management Director Randy Duncan that the new warning system works.

“The language in the impact-based warning helped all of us ... to convey the seriousness of the tornado” that struck Wichita after dark, Duncan said in an e-mail response to questions. “That language, I feel, helped to convey how serious the situation was, and the fact that we didn’t have any fatalities means – at least in my mind – that people in Wichita paid attention.”

Officials in central and south-central Kansas told Chance Hayes they liked the “real life” wording of the warnings.

“They felt the statements were more realistic and prompted action,” Hayes, warning coordination meteorologist for the Wichita branch of the weather service, said in an e-mail response to questions.

This year’s warning system includes a few language tweaks, Hudson said. The word “significant” is being replaced by “considerable” when describing the amount of damage possible, for instance. “ ‘Significant’ didn’t have a lot of meaning” to people questioned about terms used in last year’s impact-based warnings, Hudson said. What one person considers significant may be relatively minor to someone else.

When a severe threat to human life and catastrophic damage are occurring, forecasters can use the term “catastrophic” to describe the event.

Forecasters are being told to think about “what you’d tell your wife or husband or children” about the threat posed by an approaching storm, Hudson said.

The goal is to use the gravest terms rarely, he said, “but when you use them, we know you’re serious.”

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