Impact-based Warnings: Emergency Manager's Perceptions and Experiences

From assessments of large impacting tornadoes in 2011, the National Weather Service (NWS) inferred that emergency managers and media decision makers wanted a better sense of the potential impacts from storms so that they could make better response and business decisions. In response to this challenge, the Central Region Headquarters (CRH), in collaboration with a number of internal entities, devised a prototype of a modified severe weather and tornado warning message in hopes of improving decision making. The message, called the Impact Based Warning (IBW), was developed to convey a sense of severity of the potential impact of storms, thus giving decision makers more information on which to base decisions. A pilot demonstration project was initiated to test the message utility in five, NWS Weather Forecast Offices (WFO) for the severe weather season of 2012, and 35 offices in 2013. Initial assessments of the IBW utility for emergency managers indicated that the approach was on the right track. For the severe weather season in 2015, 67 offices will use a form of the IBW, with another 11 offices joining in its use by October. The goal remains to see if, by changing the message to emphasize tiers of impact severity, emergency management and media decision-making can be enhanced.

Prior to implementation of Impact-Based Warning (IBW) experiment in 2012, team members in the Weather for Emergency Management project (WxEM) undertook surveys of emergency managers and forecasters in both the experimental forecasting regions and in regions where IBW was not tested and forecasters were not trained. In those surveys, EMs felt that the use of IBWs was a step forward in providing more useful information to the EM community. Many EMs said they like IBW because it gives them more insight into what the forecaster is thinking about storm development and priorities. EMs indicated that they look for a forecaster's easy-to-understand “best guess,” to give them confidence in their own understanding of the weather situation before making decisions. To the EM, additional information in IBWs begins to convey understanding of priority of risks, and helps them build confidence. Also the initial surveys of non-participating IBW EMs showed that they believe the damage tags communicate threat better and that they likely will convey severity and urgency to the public.

Since the initial experiment and assessment, there has been much controversy about the use of IBW as to whether it will lead to complacency, bad decisions and harmful actions. Some have suggested that tiered warnings might lessen the overall impact of an initial warning, potentially causing EMs to dismiss “base” warnings, and the public to wait for a more serious threat, as indicated by the warning tag, before taking action. Others argue that the science does not exist to issue such warnings, and a false alarm or near miss after a warning with a catastrophic tag will foster greater disbelief among members of the public. Because of the expansion of use of IBW, the WxEM team repeated a more comprehensive survey of emergency managers in the spring of 2015. The results of previous research on responses to warnings suggest perception and actions exist within a complex network of information flow where EMs are trying to understand and manage risk and all communications affect their confidence and decisions. Further, we gain an informed perspective of EMs about the impact IBW may have on the public.

Given the time that has passed since the implementation of the IBW experiment, some EMs and WFOs have more experience with these warnings. Thus, we launched a survey to understand the current views of EMs, some with experience and informed perceptions, others do not, and still others are so new as to only have a perception based on what they have been told. This survey was administered on-line to a set of more than 500 EMs who have participated in a series of surveys relating to influences on their decision-making in the face of impending severe weather. In addition to eliciting information on their experiences with and perceptions of impact-based warnings, the survey also addresses their views on how they believe impact-based warnings will affect public response. The results of this survey will be presented, with implications for further research to determine public understanding of and response to these warnings.