Previously, the NWS issued severe thunderstorm and tornado warnings by county, meaning that even if a tornado was expected to impact only a very small section of a county, the entire county would be warned nevertheless ( Waters et al. National Weather Service (NWS) began issuing storm-based warnings (SBWs) in 2007 ( Coleman et al. Thus, there is much room for improvement in the communication of tornado warnings, and further research that contributes to this goal is needed. Yet, research from several recent tornado events suggests that even though warning messages are widely broadcast and received, the ways in which people interpret and act upon these warnings may be inconsistent with communicators’ intended meanings and recommended responses ( Donner et al. tornado deaths have declined because of advancements in the monitoring and forecasting of meteorological phenomena, as well as the ability to disseminate warning information via multiple media platforms ( Ashley 2007 Simmons and Sutter 2005, 2008).

These findings underscore the need for more comprehensive research on visualizations in weather hazard communication that can aid meteorologists in effectively warning the public and spur appropriate tornado protection behaviors in a timely manner. Results suggest a variety of trade-offs in viewer responses to tornado warnings based on visual design choices. Central research questions investigate 1) differences in responses across warning designs, 2) clustering of extreme responses in each design, 3) trends in responses with respect to probability levels, 4) differences in responses inside versus outside the warnings, and 5) differences in responses near the edges of the warning designs. A survey of university students is used to measure the level of perceived fear and likelihood of protective action for a series of hypothetical warning scenarios. This study begins filling this void by examining responses to color scheme and relative position using probabilistic tornado warning designs. However, the development of these new types of warnings has occurred with limited research on how users interpret probabilistic visualizations. Some broadcasters and private companies have already begun using probabilistic-style tornado warning graphics. At the same time, the widespread proliferation of smartphone and mobile computing technology supports the rapid dissemination of graphical weather warning information. The National Weather Service currently issues storm-based tornado warnings, and even more geographically specific warnings that include probability information are under development.

Recent improvements in weather observation and monitoring have increased the precision of tornado warnings.

Land of Tornadoes by Melanie S. Wolfe