Communication of Hurricane Storm Surge Threat: A Mixed-Method Analysis

To help NOAA improve the communication of hurricane forecast information, this part of the Storm Surge Mapping project examines the influence of three different color scales and two legend types in conveying storm surge risk effectively. Two methods were used in the analysis: an eye tracking experiment, and a survey of Mississippi and Alabama Gulf Coast residents. Both methods measured risk perception, helpfulness of the images, and comprehension of the message. The eye tracking experiment was able to determine the areas of the map participants attended to the longest and the pattern of their eye movement around the map. Accuracy (how well participants did on a task) and efficiency (how quickly they completed a task) values were compared among image types in five different image conditions. These conditions combine image manipulations of three color scales (green to red, yellow to purple, and light blue to dark blue) with either quantitative (in feet) or qualitative (low, medium, high, extreme) scale values. Each participant was shown a hurricane in all five image conditions presented in varying order (a Latin Square design). Graphics were also tested in a survey of Gulf Coast residents. The survey examined whether any one graphic performed better in the following criteria: 1) comprehension, 2) dose/response uniformity, 3) hazard/response uniformity 4) freedom from bias and 5) helpfulness. Survey respondents were shown images of two hypothetical hurricanes forecasted to affect their area-- one stronger and one weaker. Data are still being collected for both parts of the project, although early results indicate a great deal of variability present in Gulf Coast residents' evaluation of the hurricane images. Results from the project will be discussed in this presentation along with any recommendations for use of color in hurricane warning images.