Evaluation of the National Weather Service Impact Based Warning Tool

In 2012, The National Weather Service (NWS) began piloting a new communication tool, Impact Based Warnings (IBW), to improve public response to extreme weather events. IBW was piloted in 5 NWS Weather Forecast Offices (WFOs) in 2012, and 38 WFOs in 2013. This presentation will describe a study to evaluate IBW effectiveness, utilizing the Risk Paradigm (NRC, 2009) as an evaluation tool. Three audiences, weather forecasters, emergency managers, and broadcast meteorologists, were targeted to evaluate IBW's impact on decision-making. Methods to evaluate IBW include interviews, focus groups, and surveys. The study indicates the factors that lead a forecaster to use IBW and the consistency of use across a large geographic region. It also reveals how IBW influences the efficacy of forecaster communication of the weather event from the emergency manager and broadcast meteorologist perspective. The use of social media by all three groups plays an important role in the dissemination of IBW to the general public. By simultaneously evaluating the use of IBW by three distinct user communities, a more comprehensive understanding of hazard communication emerges.