National Weather Service expands test aimed at improving tornado warnings

The National Weather Service expanded a test it began in Kansas and Missouri into more 12 Midwestern states last month to improve how it communicates tornado warnings to the public — a response to a weather agency investigation of how the public responded to warnings of the deadly May 2011 tornado that struck Joplin, MO.

The states, Colorado, Illinois, Indiana, Iowa, Kentucky, Michigan, Minnesota, Nebraska, North Dakota, South Dakota, Wisconsin and Wyoming, as well as Missouri and Kansas, are part of a large section of the country that’s most prone to tornado activity.

The test project, called “Impact-Based Warnings,” focuses on word choice and message placement within each warning, according to the Weather Service. Warning messages can be tailored to particular storms by communicating the anticipated dangers associated with specific storms and actions people should take.

“This project was born out of the recognition that language matters, and how we convey risk can mean the difference between life and death during a weather emergency,” said John Ogren, acting director of the National Weather Service’s Central Region. “This is one of many efforts we’ve undertaken since the destructive 2011 tornado season to improve our service to America. One important lesson we learned from 2011 is that standard one-size-fits-all tornado warnings contribute to public complacency.”

“All tornado warnings indicate a serious situation, but we realize that the strongest storms and those that stay on the ground longer pose a greater risk to life,” Ogren added. “These enhanced warnings allow us to ring the bell a little louder in those situations.”

The enhanced warning system gives forecasters three tiers for their tornado warnings:

  • Common warning: When a tornado is possible based on radar data, the warning will include a bulleted list that clearly communicates hazards and impacts.
  • Considerable damage threat: When there is substantial evidence of a large and dangerous tornado, the warning will include the phrase, “This is a particularly dangerous situation,” to identify a high threat level, describe expected damage and promote urgency to seek immediate shelter. A damage threat tag of “considerable” will be embedded in the warning.
  • Tornado Emergency: When a known, potentially violent tornado is likely to produce devastating damage, the warning will announce a “Tornado Emergency” and direct the public to seek shelter immediately. A damage threat tag of “catastrophic” will be embedded in the warning.

Mike Smith, Senior VP/Chief Innovation Executive at AccuWeather Enterprise Solutions, who authored the book “When the Sirens Were Silent” about the EF5 tornado that devastated Joplin, determined in an investigation of the incident that inaccuracies in data from the National Weather Service contributed to confusion about the track of the storm and the ability of broadcast meteorologists to communicate accurate warnings in a timely fashion.